Revista de Obras Públicas de Puerto Rico

REYI5TA DE OBRAS PU

T

•I

'!

'k

jAo i

DE PUERTO RÍCj\J (EjsarTT-.-crrrrrEírxmjB

Camino

''Tierras Nuevas/' de Manatí.

tyl

cAño XII

br

il,

1935

Número

4

^Vi aM'ig?»

Sucesores Saiiturce

—

i:i

iie

vcLCi

708 C-nal

experiencia durante 40 años de

Bank

1,

Tel.

New Orleans, La. New York, N. Y.

Building,

Foot cf Wall Street, LIucllG No.

671.

—

San Juan, Puerto Rico.

técnicos.

?> "<i:

^'- *.- «r^«k.-v*>'4^J

THE SHELL {)FFI(M^]S:

sr.

STEAMSHIP COMPANY

en nuestro propio Laboratorio.

•.-<rx^^^ «^' ^-^^T-^ :

i>::r

THE NEW YORK AND PORTO RICO

Lunkenheimer, Empaquetaduras JohnsManville, Correas de Cuero Bebieren, Herramientas Starret, Aparatos de Pintar De Wilbiss, Grúas Eléctricas Mundi, Maquinaria Frigorífica York, Ladrillos Fuego Tbermo, Reparaciones y Contrastaciones de Romanas. Análisis Químicos Indusproblema con nuestros

i/.í)

i^ira iiii'íírmes diríjase a:

Válvailas

i^^>A:^fy%>:^>^^.^y^-<^>'^-^>"f^- ^"

Güclentc y rápido servicio de vapores entransporte Isxv/ York y Puerto Rico para el

servicio sin interrupción.

Motores de Gas, Bombas para Riegos, Motores Eléctricos Fairbanks-Morse, Romanas Fairbanks.

c^u

CORREOS AMERICANOS

Je pasajeros y carga.

:

Consulte

^=ii: :,r- '4:

.?:-4.^ :?^''í^-

•>-.

^

'*^^-^^"*^^^^^

?

Co.

SAX JIAX. VOXn:.

I.P R.I

.\1AYA(U1^]Z.

PETROLEU!^

Ltd.

CAOrAS, AHECIP>0

PRODUCTS

FUEL OIL DIESEL OIL GAS OIL

MOTOR GASOLINE AVIATION SPIRIT

KEROSENE LUBRICATING OILS LUBRICATING GREASES

ASPHALT FLY SPRAY 'í^v^^^^s,^?»--^-^^

ül

^ús

Puerto Rico

Taleres de Maquinaria, Fundición, Calíleroría y Forja. Constante Surtido en nuestros almacenes de Materiales para Centrales Azucareras.

triales

m ÜU

VAPvOr.ES

LNGENiEilOS CONTRATISTAS

—

gJMüJLiiJi^WJMB

roRiQ

de Abarca i\!irairíar

'

jJg. J.'

'UCñ:

n\

me

Fwmmrrm

MENSUAL

PUBLICACIÓN

Director:

RAMÓN gandía CORDOVA AÑO XII

ABlUh DE

1935.

No. IV.

wmñRim Página. lícport

nj

Counuilia- of Mineral Hrsoitrccs in

!¡K'

Puerto Rico

889

894

(Uoníjios Muniripah's

Preííhiinanj Iicport on

Mineral Devofopment of

ilic

Fue rio Rieo \\y Erhvin V. Kc-kel, Cliief GoologLst, T. V. A.

Mejonnnieiiio en

Pov

11.

la In^JusIria

Estaci/m

Por

la

al

filian

de Horticultura

900

Seeeión de Agrología de la

Experimental

Puerto Rieo

Frutera

T. (/owlor, ProiVsor

¿Qué hen ejido rinde

895

de

la

Universielad de

Pueblo de Puerto Rieo?

Ainedee l>onnet, Agrólogo

901

The Maynetife Deposit near lluniaeao, P. R. J>y R. J. 11.

(,V)¡()iiy,

.Alember

A

-

I

-

M

-

E and

A. Meyerhoff, Associated Meiiiber I-M-E

—

¡Aneas Telegráfíeas y TelefóPáginas F entra' es nicas de Puerto Rico.

903

GOBIERNO DE PTO. RICO

BÜLL LINES

OFICINA DEL SECRETARIO EJECUTIVO NEGOCIADO DE MATERIALES, IMPBENTA Y TRANSPORTE

NEW •

SEVICIO SEMANAL DE CARGA YORK-PUERTO RICO Y VICEVERSA

SERVICIO REGULAR DE PASAJEROS

San Juan, Puerto Rico.

Y CARGA

Subasta Semestral

Y VICE- VERSA CIERTO RICO-NORFOLK Y PHILADELPHIA SERVICIO INTERANTILLANO

liALTl MORE-PUERTO RICO

recibirán Ilasty, la fecha y hora fijadas para cada subasta, se sobre cerratlo, proposiciones para suministrar al Gobierno ínsuun precio fijo por unidad, tales cantidades de los diversos arla;,

Pasaje y Carga

ei'.

•

tícrk

ser sus necesidades durante

como puedan

especificados

I

el

se-

mestre do julio 1ro. a diciembre 31 de 1935, ambas fechas inclusive.

8e solicitan artículos para ser entregados en varias poblaciones, enellas Aguadilla, Arecibo, Arroyo, Guayama, Humacao, Isabela, Mayagüez, Ponce, Río Piedras y San Juan. Aquellas personas o firmar, que lo interesen, cotizarán para todas las poblaciones en las

tre

puedan prestar un

cuale-;

servicio

eficiente de entrega,

de acuerdo

con las disposiciones indicadas en cada subasta.

Término para

R\> biist

BULL INSULAR UNE

recibir ofertas

Clasificación de Artículos

.

Mayagüez

Ponce

MUELLE

1935

lu-

f]ncuadernación

ni-

Ferretería, Plomería,

lla-

Provisiones en General, Carnes, Pes-

de

teriales

Frutas,

Muebles v Accesorios Drogas, Productos Químicos, Artículos de Farmacia y Laboratorio .Abonos, Alimentos de Animales, Artículos (le Agricultura y Gana-

noli

6—

dería,

etc.

117—

Artículos

118—

Efectos, Materiales y Utensilios Eléc-

119— 120— 121—

Herramientas en General

122

Efectos de Oficina, Material de Es-

de Bazar y Quincalla, de Barbería y de Zapatería, Efectos para Limpieza, etc.

General

en

tricos

Géneros, Telas, Tejidos, etc.

Piezas,

de automóviles

cribanía, etc.

123—

Efectos

de

Dibujo,

Fotografía

9:00

a.

m.

Mayo

1

10:00

a.

m.

Mayo Mayo

1

3:00

p.

m.

2

9:00

a.

m.

Mayo

o

10:00

a.

m.

Mayo

o

2:00

p.

m.

Mayo

2

3:00

p. ni.

Mayo Mayo Maro

a

9:00

a.

ni.

3

10:00

a.

m.

3

2:00

p.

m.

Mayo

3

3:00

p. ni.

Mayo

4

9:00 a

m.

Mayo

4

10:00 a

m.

TEL. 2060

3.

Mayo

4

11:00 a m.

Nuestra Suprema

SAN JUAN

Gasolina, Aceites Combustibles y Lubricantes, Grasas y

Otros

scgarí;

dad y rapidez al públicoj

Nuestra Amable Súplica!

Pedir la cooperación del público hacia

m

posible mejor servicio»

gida por

Los modelos en blanco para preparar las licitaciones pueden el Negociado de Materiales, Imprenta y Transporte, San Juan, Puerto Rico.

Ambición:

Servir eficientementet con

Si nuestra

y

Otros

124—

1

Gomas, Tubos, Herramientas

V efectos •

Mayo

Vegetales,

etc.

114—

NO.

Maderas y Ma-

Construcción

Leche,

cado,

Arecibo

Imprenta y

Material de

Pai>elería,

INC.

Hora

Fecha

Núm.

—

SANTO DOMINGO (ÚNICO SERVICIO BISEMANAL DE MUELLE A MUELLE) SERVICIO SEMANAL ENTRE PUERTO RICO E ISLAS VÍRGENES PUERTO RICO

el

amable suplica público,

lizado nuestra

es aco-

habremos rea-

suprema ambición,

obtenerse en

FERNANDO JIMÉNEZ.

WHITE STAR BUS UNE

INC.

Jefe Interino del Negociado.

I

VISTA PE OBI A

LICA;

DE

PUEITO MICO PUBLICACIÓN MENSUAL Del Departamento del Interior y de la Sociedad de Ingenieros de P. R. para informar al Pueblo de Puerto Rico, del progreso de sus obras Públicas; para fomentar las industrias e impulsar el arte de construir.

FUNDADA EN

1924

POR GUILLERMO ESTE VES,

E.

C.

Comiisionado del Interior.

OFICINAS:

RAMÓN GANDÍA CORDOVA

San Juan, P. R.

Enitred as second class malter at San Juan, P. R., Jan.

AÑO

SUSCRIPCIÓN

Director:

Depto. del Interior.

2,

ABRIL DE

XII

ANUAL

$«.00

1924 at the Post Office under the Act of

March

3.

1935.

1879

No. IV.

Report of the Committce of Mineral Resources of Puerto Rico

By H.

A. Meyerhoff

(Conclusión)

of determining that persistent auriferous

and that the valúes In the north-central section of the Island extending

from Toa Alta to Corozal and Naranjito and as far south as Barranquitas, gold and other metallic minoráis appear to have been introduced inlo the rocks at a nuirber of points where igneous intrusions have invaded the country rock.

For the most part the gold seems to have been deposited in quartz veins, most of which are very small, although in certain places and in certain rock t^pes cxtremely numcroiis.

Only rarely, a.s in the Barranquitas district, do the veins attain even modérate widths.

The

provision-

drawn that much omes from small but numerous veins which have no com-

al

of the stream gold

inference has been

but thai sufficient concentration may have occurred in a limited number of places to support a Severa! potential localities have inining undertaking. üiercial posí^ibiiities,

been isolated but

none has as

yet been

diagnostically

At the present time some work is being done under the handicap of limited funds and inadequate equipment in the hills about two kilometers north of Ba-

ístudied.

rranquitas.

Two

short

dnfts have been extended inte

the country rock along veins and formatjonal contatt^, but

To

present,

depth.

The

- La Plata district near San Germore promise than any otlier which the Committee has studied. This district was examined and the auriferous rock sampled in 1933, but the Committee suspended hs own work when the Burean of Mines engineers investigated the property and rock samples for assay.

Al tliough a report on the results of the assaying was promised, nono has been receiví-J, and the Committee is resum-

mán

ing

date, the Minillas

offers

its

owu

study.

A spetial

report on this locality

Ls

being

prepared.

Summary Pro pecting and mining for gold are the mineral induStry's current boom activities in nearly every part of the world, yet in Puerto Rico interest in this ñeld is virtually lacking, notwithstanding the possibilities cer :

tain sections of the Island are

known to have. Present Information indieates that pannin^^ gnd rocking operations can be triei with g'ood prospects of success along many smalj streams or quebradas in the Corozal--Naranjito sec^ tion and probably in the district south of Mameyes on the northern flauk of the Luquillo Mountains. In the same localities there is

uaneial support,

tions suoaeeding .where thé ^^llUrdal

is assured PÍ gejje^Qug ^seems futile to continué beyo]3.d th^point

at

Committee's efforts have not yet reached a point where a sound opinión can be offered.

unless exploration of this kind it

vems are

justify exploration

some prospect of small

comJSj«rcial opera-

depoeit»*^and wát^r

'^^^/^Jl^f-K^^-^^^^'^^M^:

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO

890

supply are adequate for continuous operation with judiPreliminary results obtained eiausly. selected equipment.

may

be enough fine gold in the extensive alluvial deposits bordering portions of the llío de la Plata to warrant their examination as potential

by panning suggest that there

cities for

dredging.

and quantity in eacb- of the three districts mentioned; and at the present time insufficient exploratory work has been done to warrant any occurrence,

definite conclusión

1933; namely, that the exploratory development of copper for the general trade i^ not warranted. However, there is some current interest in Puerto Rican copper

in

rock sonrces in the Corozal district, the metal appears Seveto be widely disseminated through the country rock. may these ral placeas invite carefnl study, and a few of

which

specific localities

its

demand actual exploration; but none of the work done to date has brought to light any location that has the clearAt the ]y defíned indications of a commercial venture.

MiiiiUas La Plata properties near San Germán, on the other hand, commercial possibilities are somewhat more promising, and it is hoped that the laboratory study now -

in

lead to small scale mining operations, and

view, the

Committee

ploration which will

it

is

supervising some preliminary ex-

make

it

possible to reach definite con-

clusions regarding the prospectivo commercial valué of the It Ls hoped that more critical them can be offered in the next genreport of the Committee:

iiewly discovered deposits.

iiiformation about eral

progress will soon yield results that can b© used to Without doubt, the pheno-

whieh bave led the Committee to make these conservative statements would be deemcd ampie to stimulate a tiurry of prospecting and development were they found

may

desirable to determine whether the specific interest in Puerto Rican copper can be satisfied. With this end in

is

PLATIKCM

formúlate a definite opinión. niena.

on these poins.

The condition of the copper market has not improved, and the Committee has not altered the opinión expressed

can at present be designated sls likely sites for rock-mining in the Corozal and Luquillo Although the stream gold ha^ been tracked to districts.

No

concentration,

:

The presence of platinum in the placer has been

deposits of the Corozal district

ííoUl

verified

through the eouí'tesy of Dr. Gilbert H. Ayres, chemist, The quantity recoverable of Norlliamj)ton, I\Iassacliusetts. is small and nowhere, so far as observed, does platinum compose more than one or two pereent of the total metallic Its presence, therefore, seems to be more intercontent. est ing scientifically than commercially.

üu the mainland.

OTHER METALLIC MINERALS In the Committee 's report of January, 1933, oceurrences,

known

NICKEL AND CHROMIUM

or reported, of copper, lead, zinc, silver,

Choniical analyses of

:

discussed.

chromium, and mercury were briefly The investigations of the past two years have yielded new Information regarding some of these metáis,

Mesas have indicated a nickel content of 1.00% and a chromium content of 1.57%. A

but only the discovery of additional copper deposits seems

mium

have any possible economic significance. Laboratory tests have failed to conñrm the presence of cinnabar, the ore of mercury reported near Aguada, and further study of specimens from Barrio del Carmen indicates that the re-

the nickel shows a tendency to range

the above figures indícate

may

ported occurrence of the zinc sulphide, sphalerite, was Pyrite, probably based on an eiíi'oneous Identification. stained and given a resinous luster by a fiilm of limonite,

tential utility of the ore.

The need

seems to have been the mineral which occasioned the mistake, álthough the possibility that sphalerite may be pre-

madé

platinum,

nickel,

to

esnt cannot yet be denied. will be

The

Ihe limonite

recent test in a commercial labórate /y has revealed a chro-

relativo quantities of these

Arriba

in

their geographic extent

occurrences of copper have been -

Comerlo and Coamo

All the deposits consist of sulphide ores,

whieh chaicocite appears to be the principal constituent.

Near Ciales the copper has been recovered from several outcrops fícattered over a modérate acreage north and npilhweí^.t of the Ciales - Villalba cñri^tezp^. bsgmnirg spprommately at Kilometer 19 a^id 20. Ir. the Earrajiquitas - Cómerio section, ore life^.,be^n taken frcr: two shallow open along Rio Hondo in B^rio" Las Bocas, and other outcrops are reported. The oi^, .recQvered is high grade, but

mportanee (^¿Ííá3

two constituents

range in the as

wide as

completely alter the pofor systematic sam-

is

apparent

if

an effort

is

to

be

to interest prívate capital in the exploitation of the

deposits.

PYRITE:

Í7i

a3 u¿ual^ its

A

positive results obtained

the Ciales, Barranquitas

districts.

dowimpd from 1%,

pling and analyses to determine these shifting valúes and

.^ummarized under the foUowing heads

COOPER: New

content as high as 1.96% in some of the ore, whereas

with only 0,24% in one of the samples.

«oitireij?'

npon

its

mode

of

Incidental

examination

of

pyritiferous

Adjuntas carretera between. Lares and Rio Blanco has brought to light a low rocks

fodnd

ore of Las

exi)0sed

along the

Lares

-

grade pyrite deposit containning approximately the mineral.

22%

of

Unless the pyrite can be easily and cheaply

concentrated, the deposit possesses

little

potential valué,

can not compete with the higher grade European ores utilized in the sulphuric a cid plants in the Baltinipre for

it

21:í:CLLIANíEOV8 tected

i;i

METALS:

severál copper samples,

Sllver

hM

been de-

and a better idea of

its

significance as a by-prodct in the treatment of the copper ore^ niay be' anticipated if current investigations of th©

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO copper are followed by commercial

tests ,and analyses.

small deposits of lead sulphide (galena)

The

sylvania, have yielded the following results:

known at Barrio

del Carmen and reported in the upland south of Morovis have received on further attention, and no new metallk» minerals of possible industrial interest have been discover-

Something: more has been learned of the titanium ilmenite in the llumacao iro*i ore, in whicli its intímate ased.

.sociation

with tho Iron renders

rather than an

from the

list

a>s.set.

it

a commercial liabiiity,

The elimination

of miscellaneous metáis

of zinc

and mercury

and the

previously known,

failure to

two years of active field and laboratory investigations may be regarded as an indication that the Committee^s work with metallic deposits is becoming well defined, and that it may devoto less of its attention to verification, much of which i¿5 inevitably f ruit less, and concéntrate on the more jmportant quantitative studies which should lead directly into commercial exploitation. discover other metáis not

after

Sample

-

Ignition Loss

ENERGY RESOURCES: Except for extensión of knowledge concerning the lignito deposits outcropping near the ba^e of the limestone cliffs between Lares and Moca, little more can be said regarding the mineral fuels in Puerto Rico than was stated in the Committee's 1933 report.

It will be wise to watch the experimenta which are being carried out in Germany and Soviet Russia, where, by the is

0.17

0.10

0.24

0.10

99.67

99.51

99.78

Iron

0.15

0.11

0.05

0.02

Alumina Lime

0.16

0.09

0.17

0.08

Nil

Nil

0.04

may

be pos-

Puerto Rico to profit from their experience in the utilization of her lignite; but there seems to be no point

sible for

in

making prematuro experimental

efforts at the present

na and Arecibo, more especially between Dorado and Barceloneta, and their convenient location with respect to

be appropriately directed toward the

adaptation of hydro-electric energy to the utilization and

The Atlantic Ore Company has recently brought a power line into its mine and mili near Juana Diaz; and if other mining or quarryin^

processing of mineral products.

industries are established on the Island, electrification

the obvious method of handling

With

industrial

power

all

namelj^ a mainland or local market and, shipments are to be made to the mainland, an ocean freight rate which will make competition with Belgian sand possibie.

ware

f actory,

\y

It

is

doubtful w^hether the demand

t'or

glass-

in tlie Island is sufficiently large to support a local

m

but the possibility merits careful study, particular-

connection with a survey of potential uses for hydro

eectric power.

BUILDINO STONE: A

serious effort to determine

the commercial possibilities of Puerto Rican marble has

been made, but without conclusivo

Guayabal Reservoir

Attention has

to

Rio Descalabrado, and hand-trim-

blocks of various sizes have been prepared and some

them shipped

sal.

results.

centered on the limestone rhlge extending from the

be'ín

to

marble firms

in the States for apprai-

Deopile the large surf ace-outcropr^, the marble appearfe a seam of formation slightly less than 300 feet capping the greater part of the mountain in which

to consist of tliick,

the

manganeso is found. Its exposure has led to extensive and a certain amount of subsurface solution, and deformation which it has underguue was responsiblc

solution ihe

is

mechancial operations.

rates low, experimental effort

—

if

of

may

0.02

0.03

The feasibility of cleansing the sand of organic mathas been demostrated, and the utility of the washed product in the making of glass seems assurecl. The large extent of the deposits near the north coast between Caroli-

med

time.

Attention

0.03

ter

being converted to it

Trace

0.01

Magnesia

Once these countries have

perfected the applications of the process,

2

Unwashcd Washed

99.47

Silica

to be solved

synthetic petroleum products.

Sample

1

Uawashed Washed

transportation facilities leave but two commercial problems

NON METALLIC DEPOSITS

process of hydrogenation, lignito

891

may

for the

development of

ly healed.

wisely be turned toward the processing of raw minerals

mauy

cracks which have been part-

'

Because

of the chemical

solution

and

mechanieal

manufactured products. Admittedly ventares of this kind must be based upon minute and accurate studies of local and mainland markets and upon sound industrial engineering but some of the possibil ities, such as the manufsieture of pig iron and steel with the electric furnace,

be considered; and it is not surprising that an elabórate study of the depasits on the property of the Atlantic Ore Company resulted in the condemnation of the marble for

are entitled at least to consideration.

a large commercial operation.

into

;

cracking, there are reiatively few' places on the ridge where large-scale quarrying with channeling machines can even

whole, however,

SILICA 8AND: Burean

Through the copperation of the from local-

of Mines, samples of silica sand taken

near the north coast have been studied for their posAnalyses made sible utility in the manufacture of glass. by the Hazel Atlas Glass Company of Washington, Pen^ ities

it

may

ía vorable site for drilling

have been selected. sified

A

Con^idering the ridge as a

be questioned w^hether a more un-

and study ing the marble coídd

local flexure in the rocks

the fracturing at this point, an

manganeso causes rapid variations make the extraction of any nne color

the

1

ha$ inten the proxiilaity of

in color tha|; would

v^riety in 9§ecified

^r^^^^^ v>gí!?^p^i^í^

REVISTA DE OBRAb PUBLICAS DE PUERTO RICO

892

On

quantities,and sizes utterly impossible.

the local clay employed, the problems are all economie in

either side of

tho mangareé^e property, the joints or cracks are more widely spaced and the color remains essentially constant.

nature.

latter closely resembles that of the Bottieino marble,

The

which

js

small,

extensively used on the mainland and practically

using

all of which is jmported from Italy.

In view of the popularity which this type of marble despite the depression, there is good reamaintained has the marble investigations in this section of continué to son

The negativo

the Island.

limited acreage

iiigly

ganeso mine need not,

may

market

concliiisions

may be found

may

ultimately be reached

which seenis

it

is

impossible to

among

^'mLssionary work'^

much foundation

else-

to exist, the

maviufacturer must give consider-

other hand,

is

more

The demand for

tile,

on

active.

Plant loeation assumes a place of great importance not because of

raw materials but because

portation to market.

make

of cheap trans-

Bulk, relativo fragility, and weight

large hauls impossible; and

establish a brick-tile industry,

it

if it is

will be

contemplated to

sounder economy

building

to orect several small plants at strategically scattered points

aetivities of the Federal Relief agen-

demand. There need be little concern about satraw materials although careful sampling and testing must precede and guide the precise loeation of

the

The

:

constructional projects has

made

cement supply one of immediate

the subject of a

interest.

Edwin

C.

Eckel, Chief Geologist of the Tennessee Valley Authority,

made

without

than one or two plants equipped to supply the Island 's

CEMENT local

lh(í

lo-

trades.

cies in

is

;

re-

Sta-

This prejudice

northwestern and southeastem

in the

Whatever the psychological background, the demand for bricks is small and, unless the government program of home construction overcomes the prejudice

for marble slabs and for marble

have never been gathered, and

and some

I

able attention to sales resistance.

guess the possibilities without careful analysis of the market

be warrante

where.

results obtained in the exceed-

aggregate in synthetic stone and concrete products. tisticts

for construction because of the danger of failure

corners of the Island but

which was core-dril led at the manby any means, be assumed to apply

garding the prospects for dimension-block quarrying, a cal

it

brick structures during earthquakes.

in

to the entire ridge.

Whatever

The two principal elements are market and trans* At the present time the market fot brick is and here appears to be some prejudice against

portation.

study of raw materials and potential sites for a cement plant in October and November, 1934, and his report on this and other subjects relativo to the development of rock and mineral resources has obtained wide eirculation. Mr. Eckel hajs concluded that **good cement can be made at a number of points in Puerto Rico", and *'strongly recommends that a government plant be undertaken." The Committee reached the same conclusión

entiro

isfaetory

each individual plant.

a field

concluding in

three years age, '*the creation of a

CEMENT

its

report of 1933 that

industry becomes a problem

which will mean a saving The Committee feek called upon

of economics, the solution of

in

consttruction costs."

to

MISCELLANEOÜS: No made

further

study

has

been

of the other non-metallic products discussed in the

1933 report, but several new^ possibilities have been developed. Some attention has been given to deposits of silica resembling diatomaceous earth, which may find use in

and scouring powders aiyJ other abrasivo proMr. Eckel of the T. V. A. concurs with the suggestion of our Committee to erect a paint mili for the manufacture of mineral paint which will utilizo the limonite of Las Mesas as a base. polishing

ducts.

R ü

reafirm the economie charaeter of the problem, and to

S

U M E

point out the fact that the Eckel report was not desig-

nated to deal critically with the economie factors. The Committee has in preparation a detailled study of the subject which will be published as a sepárate report.

It is hoped that the report will serve as a basis for final conclusions and definite course of action regarding the making of cement in Puerto Rico.

CLAY PRODUCTS: A has been given to

somewhat similar Ímpetus consideration of a brick and tile industry

as a result of current housing projects.

a charaeter suitable for brick, d¿.tr:buted,

and

tests

tile,

have already

:r-d:e2,ted

ty cf ene large residual clay depofit at skirts of

Clay deposits of

and pipe are widely the suitabili-

t!ie £Out!ier:i

cut-

Rio Piedras.

Brick and tile manufacture involve the making of a low cost, high-bulk commódity; ajid once the procesa of ipaunfaoture is aáapted to the special characteristics of

Two years of field examination and laboratory research have confirmed the conclusions offered in the Committee report of January 7,1933, although many details and a somewhat different order of importance must be assigned to the six itemized

statements offered at that

time.

Partly because of the data which have been ac(1) cumulated, but even more because of the increased valué of gold in terms of dollars, placer gold seems to offer the. brightest prospects of immediate economie development.

Sites mxist be chosen and equipment selected with discretion

;

the element of chance must be f rankly recognized, not

in the p:c¿e::oó cf ¿^cld in

enough

«illuv:u::i to

but in the persistenco ^t valúes sustain operations over a, piriod of

time sufficí^ently long to liquidate the investpient.

Intelligent exploration will greatly reduce the risks -— perbaps eliminaet tkem entirely; and the initial invo^t-ment

:

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO is

not large enough to ocoasion any serious ultímate loss.

The inereased production of manganese in the (2)

Juana Díaz district, the exploratory work near Adjuntas, and the diseoveries in Bartolo and Aguada point to manganese as a resouree with definite potentialities. A few problems and many milling and metallurgical problems still await solution, and it may be that some of them are But manganese is present and is widely disinsoluble. tributed it will take initiative and some capital to explore its possibilities, and even in the event of failure, the loss

893

capital that will intelligently develop the Islandés mineral resources.

Respectfully submitted, Br.

Ramón Gandía Córdova

Manuel Egozcue Benjamín J. Horton Felipe Carro William D. Noble

Manuel V. Domenech Santiago Claudio

;

may

be greatly offset by incidental recovery of ore. Possibly developments must await more complete recovery of the steel industry, as we]l as a fixed ])olicy with regard

manganese imports on the part of the Federal Government; but exploratory w^ork may wisely be done in advance if it is to enjoy the benefits of an improving market.

Howard A, Meyerhoff

Dr.

Hcliodoro Blanco Guillermo Esteves

COMMITTEE. ¿5an Juan,

Puerto Rico. January 31, 1935.

BIBLIOGRAPIIY

to

The magnetic deposita

(3)

of eastern Puerto Rico are

known, their commercial valué more fully, though not completely, established. Here again exploration should anticípate any possible utility the ores may find in an expanding steel industry; and even though exploration demanda an optimism wliich current conditions to not strictly justify, it acquires pertinence and immediacy when one considers the dwindling reservéis of the Lake Superior dis-

Additional details regarding sources

may

Island's mineral re-

tlie

be obtained in some of the foUowing srtícl^e,

published since January, 1933

GENEUAIi

better

Domenech, Manuel V.: Mines and minerals de Obras Públicas, May, 1934,

p. 625.

el

al

sos

The limonite of Las Mesas and quantitative studies,

(4)

qualitative

terest in its

commercial

still

needs and merits

August, 1934,

Among

—

p. 573.

Recur-

Revista de Obras Públicas,

Minerales de Puerto Rico. p. 691.

as current prívate in-

possibilities demonstraes.

llulhard, Bela:

Geology of the Lares

District.

Revista de Obras Públicas, June, 1934.

(5)

Mjipa de Puerto

cual se indican los Recursos Naturales de la Isla.

Kevista de Obras Públicas, February, 1934.

trict.

now

Puerto Rico. Revista

Ramón: Informe que Acompaña

Crondia Córdova,

Kico en

in

p.

Mineral Resources.

C52.

the non-metallic products, the silica sand

possesses an established commercial utility but

seeks a market which prívate enterprise

may

still

Jaclson, Chas. E.: Informe sobre Depósitos Minerales en Puerto Ri-

be able to deco.

velop more effectively than a government committee.

Cement, clay products, and building stone are of immediate interest because of the Federal Relief projects.

As industries, however, they demand analytical study of the economic factors connected with their development before the heavy investments they require, are made.

Meyerhoff,

Revista de Obras Públicas, June, 1934,

Howard

A.:

Geology of

p. 665.

Puerto Rico.

University

of

(6)

Puerto Rico.

Monograph, Series B, No.

1,

1933.

NoUe, W. D.: Comité de Recursos Minerales de Puerto vista de

Obras

Públicas, April, 1934.

Rieo.

Re-

Report of Investigations.

787.

Revista de Obras Públicas, December, 1934, p.

(7)

be found, abrasives

A

possible outlet for Puerto Rican copper

if

the deposits are adequate; mineral paint and

may

may

offer opportunities for modest business endel

terprises.

Once again the

A

«tressed.

sources

CEMENT

basic needs for accurate data

fabricación de cernenValle Zeno, Bafael: Anotaciones sobre la Públicas, September, Obras Revista de to en Puerto Rico.

1934. p. 730.

must be

volunteer organization w^ithout adequate re-

cannot

expect to carry

investigations rapidly

through to a successful conclusión, for

its

fact-finding

is

Kohle,

W.

D.: Report on a cemnt plant.

November, 1934,

p.

765.

Considerations and studies for a

Puerto Rico.

limited to certain field

government cement plant

minations.

Públicas, Jantiary, 1935, p. 832.

and qualitative laboratory deterFundamental to further progress is a pc;-

manent Insular Burean, with a paid, full-time staff equipped to carry on geologic, mining, metallurgical, and economic investigations, to advise both government and prívate mineral enterprises, and to find and encotirage prívate

Revista de Obras Públicas,

in

Revista de Obras

GOLD Noble, TV. D.:

Metalúrgica del Oro.

Revista de

Obras

Públicas,

-\iW^;:-

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO

894 September, 1933,

Abstract in Mining and

Eng., Tech. Publ. No. 587, 1935.

p. 491.

Report on placer gold investigation of the

Metallurgy, February

district of Corozal

and Naranjito, Revista de Obras Públicas, August, 1934,

1935, p. 114,

p.

Revista de Obras Públicas,

Mvyerhoffy H. A.: Iron in Puerto Rico.

692.

March, 1934, Wright, C. A.: Report of investigations.

December, 1934,

p.

595; May, 1934, p. 635; August, 1934, p. 704.

Revista de Obras Públicas,

MANGANESE

p. 787.

IKON Colony, R. J. and Meyerhoff,

Humacao, Puerto

Rico.

11.

A.:

The Magnetite Deposit near

Howard

Puerto

Obras Públicas, September, 1933

p. 489.

Wright, C. A.: ta de

American Institute of Min. Met.

Manganese

in

Meyerhoff,

A

A.:

Revista

and manganese.

brief report of gold placer

Obras Públicas, October, 1934,

Rico,

de

Revis-

p. 742.

CAMINOS MUNICIPALES La comunicación en

la

isla

entre pueblos es problema resuelto

con nuestras carreteras insulares.

2,000 kilómetros, la

mayor parte de

estos asfaltada, brinda

alberga en su seno virgen.

El impla.ntamiento de centrales azucareras en Puerto Tí ico,

acrecentado en los últimos treinta años, ha hecho

y ha hecho posible

pasar a pocas manos la posesión de tierras fértiles situadas

desarrollo de la agricultura en acjuellas zonas servidas

en las vegas y sobrevegas que antes estaban distribuidas

facilidad a este transporte interurbano el

cía 1 mente se

Su red de

CAMINO MUNICIPAL -DAMIÁN,^' DE OROCOYIS, las

Construido por el Departamento del Interior. nuevas <íonstrueciones)

con su correspondiente contribución al progreso actual.

Pero fuera del alcance de esas carreteras, hay muchos centenares de miles de cuerdas de terreno que no han recibido el bautizo de la "superficie macadamizada'^ del camino que traiga a esas vías establecidas el fruto que poten-

entre

(Típico

d(í

un gran número de propietarios.

Esta centralización de las riquezas, que antes estaban distribuidas, tes

y

disminuyó

el

número de pequeñas terratenienmontañas espe-

estos se fueron a la altura de nuestras

ranzados con posibles explotaciones de terrenos en esa zona.

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO Bien pronto

se dieron

cuanta de que la carencia de

895

de caminos distribuidos en los 75 munieipios de la isla a razón de unos veinte (20) Kilómetros por cada municipio.

Esto daría casi un (1) Kilómetro de camino municipal

vías de comunicación limitaba sus actividades agrícolas en esas fincas y se inició la ''espera'' de su construcción para dar impulso a estas actividades.

El dinero adquirido con la venta de sus tierras de aba-

afirmado por cada Kilómetro de carretera insular.

Para llevar a cabo este plan ise dispuso que

jo sirvió en los primeros años para prolongar la ''espera''

de

y luego, paulatinamente fué decreciendo sementando el niimero de pobres.

La "altura" les o

entusiasmo y

ellos se

la

replegaron

mente de aquellos que

al

corazón de

la isla.

El sueño se transformó en "pesadilla" y nuestros pequeños propietarios de altura, escasamente ayudados por lo» municipios arañaron en las faldas de nuestras montañas "atrechos" y "-veredas" con pendientes y curvas fantásticas por las que "apeaban" a lomo de "chiringos" sus escasos productos agrícolas a costos prohibitivos

Y

venta.

por

estos

para

la

"rasguños" sinuosos en nuestras monta-

que discurren las aguas pluviales son los llamados caminos municipales de barro de los cuales, y como expresión de su gran necesidad, hay inscritos en el Registro del Departamento del Interior más de siete mil ñas,

total

los

el

1ro. de Julio de

1932 exclusivamente en

estudios y construccióu de dicho plan.

ciadam.eule,

menos de

la

Pero, desgra-

sexta (l|6) parte de ese produci-

podido ser dedicado a ese objeto ya que a virtud de

do

lia

la

crisis

por acción posterior de la

reinante, ese fondo,

Legislatura ha tenido que ser usado en su

mayor parte

para atender urgentes nece¿;idades del Tesoro público.

Con

los escasos

fondos disponibles se han podido consuna longitud de 166 Kilómetros

truir caminos afirmados en

y practicar estudios y preparar planos para unos 400 Kilómetros.

las

(7,000) kilómetros.

La

cts.

invertido desde

seguía olvidada y los caminos municipa-

secundarios solo estaban en

"soñando" con

el

el

fondos recaudados por concepto del impuesto de 7 por galón de gasolina consumido en Puerto Rico fuera

los

escasez de caminos secundarios afirmados en Puer-

puede apreciarse sabiendo que solo tiene la 1|10 parte de un Kilómetro de camino municipal afirmado por cada Kilómetro de carretera insular, mientras Francia, por ejemplo, tiene 10 kilómetros de caminos municipales afirmados por cada Kilómetro de carretera nacional. En otros palabras, Francia tiene cien (100) veces más caminos municipales afirmados que Puerto Rico y a ello debe su riqueto Rico

za agrícola proverbial.

Para atender necesidad

tan urgentemente

nue-stra Legislatura decretó el estudio

sentida,

y construcción

del

N'uestros legisladores, convencidos de la imj)ortancia

de este problema y animados del mejor espíritu de cooperación, han aprobado unánimemente en esta sesión de la Legislatura una Resolución Conjunta que abarca la idea de un empréstito a pagarse con la contribución sobre gaso-

una larga serie de años a bajo tipo de interés para acometer en grande escala el plan general de 7,000 kilómelina en

tros de

caminos afinnados.

aprobada en definitiva, como se espereplegados en la ''altura" poagricultores pobres ra, los ''atrechos" y "veredas" transformados en drán ver esos Si esa ley fuese

y en vez del lomo de "chiringos" será que transporten sus productos camiones sobre el chasis de de pobreza y haciénsituación agrícolas, cambiando así su carreteras afirmadas

dola cambiar también a la isla entera.

de Caminos Municipales de la Remayo de 1931.

Este plan abarca una longitud de 1,500 Kilómetros

I*lan General Preliminar

Rafael del Valle Zeno,

solución Conjunta No. 74, aprobada en 14 de

Ingeniero Civil.

Prelímínary Report on the Mineral Development of Puerto Rico

By Edwin

C. Eckel,

Chief Geologist, T. V. A.

My

visit to

Puerto Rico in October

was designed primarily to study the a cement plant at that island.

-

November, 1934,

possibilities of erecting

But, in the course of that

work, opportunities were offered to study other mineral

and

am, therefore, submitting a preliminary report upon such of thase possibilities as seem, in my judge-

possibilities

I

ment, to be worthy of the consideration of the Insular Government or of any other Federal agency interested in

In suggesting that fitably be undertaken at the moment. developnu'nt of any of these mineral products seems likely to be profitable, I am explicitly leaving off tke question as to

tlie

methods to be adopted

«orne cases,

it

in such development.

In

American

is possible that local or other

can be found'to take up the development in others, seems more likely that government encouragement and control of some sort will have to established in order to se(tapital

;

ií

the order of their actual future importance, but rather in

cnre any progress within our own lifetimes. The Island as exist are is not rich in capital and such accumulations

the order in which I think development might most pro-

in the

the problem.

The items are not

necessarily taken

up

in

hands of people whose

interests like exclusively in

HOSTRANDO LAS LINEAS TELEGRJ .FICAS Y Pan GtQoaiSftKoT

tu

PAftA'ÁCOMPARAft ÍL iNrOR

1^-1953

pin

Jiwn

P.

a.

Junio 9d 1959

"ELEGRÁFICAS Y TELEFÓNICAS

IPAÍUft EU

iNrORMC At^AL 0£

\gS2-lS53

EN OPERACIÓN

.-í'JrPr:? V

''^

cj^-'r»-'! 4 "*,'^,g:??*',/'-j,

,

-

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO

8^8

the unes of sugar, coffee, stfeamships,

utilities,

etc.

Un-

always difficult to secure

der sueh circüninstances it is adequata local backing for a mineral enterprise and still more áifficult to secure honest and capable technical advise

and

It is for these

control.

reasons that I feel

many

mineral possibilities of the Island wiJl have to be, at

of the least,

government supervisión, and some of them niay have to be retained under .such control throu<y-

started under direct

out thf

ir

increasing quantities

and most of them

will be

is

me

PORTLAND CEMENT

—

While on the Island

E

visited a large number of localities and took many samples of limestoneís and clay with the object to deterniining their

m

manufacture of Portland coiueiit. Oidy a few of these samples have as yet been reported on; the remainder are still in the hands of the Burean of Standards at Washington and of the University at Puerto Rico. When the results are^all in hand I will prepare a sepárate report upon the cement possibilities of the Island. In order to meet an emergency, I have submitted, as of November 10, the

a statement covering

my

estimates of costos for a plant

Cataño 'opposite San eluan and the manufacturing costs at such a plant.

built near

of

my

estimates

con-

go over the project of Mr. Aaronson whó government tile works near

to

interested in establishing a I visited

Kío Piedras.

the several possible localities with

Mr. Aaronson and agree entirely as to the feasibility of My suggestion is, however, inaking tile at those points. jhat in building a tile plant, in place of building

entire lives.

m

Island. Mr. Bourne, Ilead of the P. R. E.

While inthe R. A., a.sk

(stablishment to su])ply the entire Island,

utility

used

nection with some government operation.

one large

we keep

in

mind

that transportation costs are high on products which are low píicoíl tor tlipir bulk, and that the breakage on such

producís

í'iay

lopíifpcl in

llic

ín place of one large plant

vcry large,

is

Juan región

í^an

I

would, therefore, suggest San Juan,

that plants of about npial size be iocated near

Mayaguez, Ponce and perhaps other points which have a faii- local market and from which shipments could be made to sinaller towns.

The

entire

amount

not serious; Mr. Aaronson, I believe,

of is

money involved

is

asking that $25,000

I should think that perhaps four, smaller plants could be constructed for not over that total, and that since there is no expert chemical control needed for such products, that one really

be set aside for the single large plant.

three, or

manage all With the exception of this and number of plants, the project

highly trained technical superintendent could

any that where Island the on localities of number large are a there raw as far so undertaken be could manufacture cement

As

a general statement, however,

these hundreds

safe to

considerations, how-

Economic

materials are concerned. ever, limit

it is

rom Cataño. Under such conditions, it government will be profitable if some reliable person in the what possible, manner as service determine, is as quiet a the reavailable in tracts of limestone and clay lands are actual securing The matter of gión, and at w^hat prices. f

options can safely rest until the analyses are received, when we can fix the location more closely. But it would, obiou^ly, be extremely dangerous to have the Information

broadcast that the limestone hilb near Cataño would be

raw material

CLAY PRODUCTS in a large way,

supplies.

— The Island uses chiy products

ranging from common

tile

and brick up

to

There are severa! small tile works the Island, some of which are still in on ready established There

is

to

size

moment.

al-

no great

of good red-burning brick

difficulty in securing supplies

and

tile

MINERAL PATNTS

—

Perhaps the most profitable

small industry in relation of net returns both to capital cmployeJ and to cost of raw^ materials, is the mineral pig-

ment industry. Groung dry colors sell in the mainland markets at from $20.00 per ton upward. In most cases, each can be produced at from $5.00 to $10.00 per ton and they are often made from very common and otherwi^e use;

raw

less

materials,

I

feel that the

Mayaguez

District of

Puerto Rico offers an unusual opportunity in this regard i\ud cannot stress too strongly my suggestion that the

manufacture of paint be undertaken by either government At he request of Señor Menéndez or private interests.

November 12, a statement concernprepared, on Hamos, I ing the actual costs of constructing a paint mili,

and

I

a])pend a copy of that to each copy of this report.

household pottery.

operation.

a's

earliest possible

much more bulky product we most

manufacture cióse to good transportation. My feeling is that regardless or whethcr the plant is owned by the government or buiit by a private concern it will almost necessarily be placed on the south side of San Juan Harbor,

the base of our

correction

scems to be entirely worthy of government, attention at the

of possible localities

closely, because, obviously, for a

and not very far

of them, visiting each hi turn.

clays;

it

is

iron ores near iMayaguez are very high grade and xery large tonnages, perhaps up to several hundred million tons. If, in the next decade, the world trade

The

exist in

in

iron should

possible,

indeed, that in the interior portions of the Island whiteburning clays of higher grade may yet be found. But for

our prcsent purposes the chief stress should be laid upon the extensión of ordinary brick, roof tile, drain tile and sewer pipe manufacture. These products will be used in

renew

its

growth there

will

undoubtedly

a time when these ores will be exported in the manuBut, at the present time, the facture of iron and steel.

come

Steel

trade

is

not in need of ores

from new sources

of

I am not counting upon Puerto Rican iron ores as giving any help to the Island within the next ñve years. Under these circumstances, I am stressing the fact hat we can use several thousand tons

supply, so

the development of the

a year of ores in a highly profitable

way

as a basis for

REVISTA DE OBRAS PUBLICAS DE PüEETO RtCO making good mineral pigmants already

discussed.

V

SEA SALT

— The Island of Puerto Rico does not con-

producers might be a justifiable govemiaent

áct, botli

the standpoint of expedieney and profit.

As

and

leaS

zinc, the prospects

'

írom

to eopper,

do not seem to be worthy of

any deposits of rock salt, but it has the possibiiity oí" making evapora tecl sea salt very eheaply owing the climatic conditions. At present, or in the very recent past, sea salt has been made at points on the south coast extending from Cabo Rojo, Parguera, Guánica, Ponee, Santa Isabel to

Among the non-metallic mineral products which it seems might be developed are deposits of tale, glass sand, and distimaceous earth and volcanic ash. Of these, I was

Guayama; while

able to visit a

í.ain

at

one point on the northwest córner of manufacturing still imports most

the Island near Isabela

and a large proportion of this coarse form of salted fish a still larger tonnage of salt Ls brought in from Nova Scotia and Newfoundland. ít is my feeling that tho trade in this commodity can be improved very easily in two directions First, the produetion of more salt on the Island should replace the salt Qow imported as sueh. Second, salts produced on the Island could profitable be shipped to Nova Scotia and New-

lurther consideration a the present time.

number of localities of the glass sand but have known oidy from samples at San Juan. feeling, however, is that all four exist in commercial

the oíhers

I

of its fine table salts,

My

salts; while in the

and that their development could be undertaken with reasonable hope of success. In the lack of definite

—

foundland, the

sources of

cliief

our

salt fisch

imports.,

neither of whicli British territories produce salt of their

At present, the sources of supply for the industries are off lie Spanish coast and Turk's Island in the West Indies. íf we would introduce Puerto Rican salt to those own.

we could

í^orthem markets,

Mim,

wiiirli is

oecM [is

both

a!>;(>

iii

receive in return erude gyp-

pro'Juced abundantly in

Newroiindland.

The

oí coiirse, that its

is,

oceau water and

its

fiud

is

simply

simply the heat of the sun.

enough of

I^uerto Kico natiually has

is

Rut

pi'oducts.

both.

ieiiotli

cussed,

PRODUCTS

—

do not intend to suggest hat there were no other

mineíals on the Island whose dev.elopment íibly

In speaking at

on tho four mineral products which have been dis1

be attemptc-e.

í

am

may

not reason-

strongly suggesting that these

four presen t the most attractive features from he standpoint of f^ovemn-^rt ^:^r;^;iirenients

and that

ment shoidd be aided or accomplished

At

present, there

high grade

—

manga nese

is

their develop-

first.

a modérate production of very

ore,

a very small output of gold

and that about covers the actual mineral output of the In my judgment, the manganese shipments are

island.

likely 1o incrcase in

twenty years.

futuro for, perhaps, the next ten or

it is possible that if a

made

more careful study

might suggest government and í^iade of manganese deposits than those which are now woiked. As to gold, 1 have been the working at severa! points and agree entirely with Mr. H. D. Noble that a more extensive output could be .secured by very simple oí'

the situation could be

I

aid merely to the extent of determining the location

m.eans.

I

am

not prepared, however, to

more than

$10,000,

aid to

would be a highly and I certainly

profitable investment for a prívate firm;

the sand, volcanic ash and diatomsceous easth

feel that

have to receive our attention as soon as a cesince all three of them can be used in connection with that cement in the manufacture of superior grades of concrete. tieposits will

ment plant

is built,

-•

In closing this |)relinnnary report

recommend that

I

thínk

it

my

duty

your mineral development lack of local experts on such

to cali attention to the fact that

by the en iré There are excellent

will be retarded

civil and hydraulic engineers on the Island, there are expert sugar chemists and agricul-

matters.

But

1

fio

not

thínk that, today, there

i^

a single geologsit, mining engineer, metallurgist or mineral cliemist

serious

anywhere we are

if

in

Puerto Rico. This deficiency becomes put government money, or en-

lo either

courage prívate capital,

lo take part in the

of Puei-to Rican mineral resources.

I feel

development

that one of the

steps should be the organization of some simple tech-

fii>^t

burean competent to take charge of such matters. It is not necessary, ñor ¡n(;eed desirable, to place such a burean on a very extensive or permanent footing. My feelnical

ing

is

that

it

should be handlel

in

a rather

simple and

inexpensive fashion by temporary details from some of the

maínland organízations and

in case this suggestion

meets

with the approval of the Secretary I should be glad to place the idea in nu)re definite form.

The present commi-

on mineral resources, which seems to be an entirely voluntaiy and unpaid organization, is composed of highly

ttee

honorable and

i)atriotic

gentlemen.

smaller allotments which as gold

I

I feel that

any of the

have suggested for sueh things

mining and similar mining industries could be

placed in the hands of Mr.

W.

D. Noble, Secretary of the

But I do not feel that equipped with eiher competent

committee, with absoluto safety. the committee

is

at present

do much mgre han act minor government allotments. I am personally very deeply interested in this whole matter and

Ihe goveinment go very far in direct operation of such

staff or adequate laboratories to

though 1 feel that supplying proper information and perhaps leasing some items of machinery to actual

as stewards for such

de])osits,

feel justified in re-

grinding mili, which would

I feel that a tale

not cost necessarily

tural chemists.

OTIÍER MINERAL

do not

I

the government extend direct

it

chief advantage of the

raw material

that

prívate producers in any of these four possible mineral

in

plaster and stucco producís. salt industi'v

Scotia and

responsible technical control,

commending

This gy p.sum could be used the local manufacture of

our ceinent mili aiul

iii

Nova

quantities

m

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO

wñl be glad to discuss any of those higher in

it

further

if it

seems of interest to

authority.

Respectfully Submitted

he asked me very specifically for an immediate Under those statement regarding the eeiuent situation. stateaceompany-ing prepared the circumst anees I ha ve in Gruening, Dr. iiieiit and am sending copy to you and to

November

8,

(sgd.)

Edwin

may

be at least equally well informed as to what has been said so far. My personal feeling, from the interview, was that Mr. Chapman and perhaps Secretary Ickes were somewhat strongly inelined toward governníent order that you

C. Eckel,

Chief Geologist, T. V. A.

and that they will examine any commercial critically. But whatever you may decide I think you can feel assured that good and cheap cement can easily be made on San Juan harbor and T wish you every

operation

TENNESSÉE VALLEY AÜTHORITY KNOXVILLE, TENNESSÉE November

offers

10, 1934.

very

snccess in that matter.

Thanking you for

Kis Excellency,

The Governor, San Juan, Puerto Rico.

líiy

visit in

Very

My

dear General

all

the eourtesies extended during

Puerto Rico and

New

I

I

am

respectfully,

:

Edivin C. Eckel,

(Sgd.)

When

York,

saw the Assistant Secretary

Chief Geologist.

of the Interior on

MEJORAMIENTO E N LA

IN DUSTRIA

FRUTERA

Por H. T. Cowles, Profesor de Horticultura

Uno de los entorpecimientos más- grandes con que el frutero se encuentra en su finca es el daño que hacen los insectos

y enfermedades

Se ha estimado que las pérdidas en las toronjas ocasionadas al disminuir la calidad de la fruta han llegado anualmente a la suma de a la toronja.

$100,000 sin tomar en consideración

reducción en la eficiencia del follaje de los árboles atacados por el hongo.

No importa

lo bien

que haya cuajado

la

el

fruto

si las

condi-

ciones climatológicas son adversas, las frutas tendrán que

venderse a

muy

minado en

el

Adoptando un plan deterpuedan asperjarse los árboles a su debido tiempo, muchos agricultores están haciendo un comPor ejemplo, utilizando pulbate eficaz a sus enemigos. verizaciones de caldo bórdeles, se puede dominar el hongo bajo precio.

cual

que causa la roña en algunas plantaciones de

la costa nor-

El período crítico es el intervalo entre la época de la te. floración y la época en que la fruta ha alcanzado un diámetro de unos 3 cm.

De acuerdo con las recomendaciones de los investigadores, el frutero puede producir una buena cosecha de toronjas mediante el uso de una solución de azufre con cal cuando se encuentra con el acaro en esta época del año. La concentración más propia para asperjar es una parte de solución de azufre con cal por 66 partes de agua. Se debe aplicar la aspersión cuando hay pocos ácaros presentes,

antes de que ocasionen cosecha,

mucho

daño.

Durante

la

presente

el

noventa

1'^,

siguien-

un frutero de Arecibo pudo obtener

por ciento de su cosecha clasificada "U.

S.

No.

do un programa de aspersión para combatir

los

ácaros de

La solución de azufre con cal ejerce solamente mitad del efecto que puede tener la solución de caldo bórdeles, pero ayuda a reducir el daño que hacen las queroí^as y los ácaros.

También^ no causa una reducción severa en los entomomicetas que ayudan al agricultor a disminuir las plagas de queresas.

Otro paso importante que pueden abordar los agricultores en el presente es la erosión de los suelos.

Al lu

toronja.

la

ti

abajo de evitar

ha prestado atenmayor esfuerzo de parte de

la erosión excesiva se le

ción durante los últimos años

;

de esta isla debe hacerse, si no se quiere queden permanentemente estériles, debido a la pérdida del suelo superficial.

Las generaciones venideras también necesitarán un terreno propio para los productos agrícolas. Hasta hace poco, solamente una pequeña parte de la tierra bajo cultivo en las lomas se trataba de tal manera que se pudiera conservar la fertilidad para Demostraciones de cómo hacer terrazas en Utuael futuro. do, San Sebastián y otros sitios se han repetido con entulos agricultores

que

las fincas

siasmo por* parte de agricultores progresistas.

Después

de demostrar que una inversión de $2.00 por cuerda en

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO hacer terrazas para evitar pérdidas de terreno, un agri-

tiernas

año en un proyecto de 200 cuerdas. El valor de una inversión tan pequeña no se puede predecir pero es muy sencillo deducir que se puede esperar un aumento considerable en el valor y fertilidad de la tierra en 10 años.

zas,

cultor ha decidido preparar 27

más

este

Otro método que puede adoptar el frutero es hacer qu4 agua corra por zanjas hechas de acuerdo con el contorno dei terreno, haciendo que el agua se empoce en sitios donde l)uedan recuperarse el cieno y humas que restan a la fertiel

lidad si se pierden del terreno. El costo es solamente $4.00 por cuerda y cuando se implante el sistema propiamente, se ayudará a contener el agua de fuertes lluvias durante la

sequía de la primavera.

Se está progresando en la introducción y desarrollo dé mejores variedades de vegetales y frutos para consumo en el hogar y para exportar al mercado neoyorquino. Hasta hace poco, apenas se podía encontrar vegetales frescos y en abundancia en el mercado local. Ahora, tomates de buena clase, pimientos de calidad mejorada, habichuelas

¿Qué Beneficio Rinde

al

la

y abundantes repollos, como también otras hortalipueden encontrarse en nuestro mercado. Por medio

de demostraciones en las sub-estaciones, el tomate *'Marglobe'', el pimiento ''California Wonder'' y las habichuelas ''Bountifur^ han probado adaptarse bien a las exigencias del

mercado.

Al mismo tiempo nuevas variedades que prometan hacerse necesarias en el mercado, están siendo mejoradas por

Arturo Roque, en la Estación Experimental. El vauna nueva variedad de berenjena resistente a la marcliitez puede alcanzar a miles de dólares.

También está desarrollándose una variedad nueva de i)epinillo resistente al añublo que puede añadir como $50,000 al bolsillo del ao-ricultor en los próximos diez años. el

Sr.

lor de

No

se

puede terminar

los trabajos

gorgojo,

esta breve reseña sin

importantes del Señor Seín, en

mondando

la base

de la semilla,

mencionar

combate del como también la el

ventaja del uso de abono para café })ara evitar la caída del grano,

la Sección

Experimental de

901

recomendado por

el

Señor Vicente Medina.

de Agrología de la Estación

Universidad de Puerto Rico

Pueblo de Puerto Rico?

Por Juan Amedee Bonnety Agrólogo.

La Sección de a su cargo

el

Agrología, creada en julio

1,

1931, tiene

estudio de los suelos de Puerto Rico.

Programa de Trabajo:

los

El trabajo principal comprende dos fases: 1 Cooperación en la clasificación científica de Rico (Estudio Edafológico).

Puerto de 2

— Investigación

clasificación

los sue-

científica

correspondientes es la base

Negociado de Quí-

clasificar los suelos

de labor.

El mapa siguiente demue-stra el progreso del estudio Cada área enumerada fué Por considerarlo conveestudiada independientemente.

técnica.

edafológico desde 1928 a 1934.

ESTUDIO EDAFOLÓGICO La

sificación de. Suelos (Soil Survey), del

mica y Suelos, Washington, D. C. Esta División Federal, hábilmente dirigida y reorganizada por el Dr. C. F. ]^»Tarbut, autoridad mundial en suelos, posee un caudal de treinta y cinco años de experiencia que ha contribuido a adoptar y perfeccionar un sistema científico y práctico para

:

niente, las secciones 1, 2,

de los suelos en unidades

fundamental para llevar a

^ido englobadas en

3, 5, 8, 9,

un informe

13 y parte de la 7

han

parcial que se intitula:

Survey of the North Coast Área, Puerto Rico."

''Soil

ca-

estudios técbo eficientemente una labor organizada sobre obra de esUna labor. de suelos nicos relacionados con los de una servicios los requiere ta magnitud e importancia competentécnicos de compuesta organización adiestrada

Como

la

información ofrecida por el estudio edafolócomo básica para llevar a efecto un

gico es considerada

l)rograma sobre la rehabilitación agrícola del país,

el Se-

cretario de Agricultura de los Estados Unidos ha asignado

el con experiencia en esta materia. Afortunadamente, Rico Puerto de Comercio Departamento de Agricultura y Universidad de y la Estación Experimental Aerícola de la con la proyecto este P. R. vienen, desde 1928, realizando

$15,000 del fondo de elaboración de azúcar de Puerto Rico para continuar durante este año (1935) el estudio edafo-

cooperación conjunta de las centrales azucareras y terrateuiente$ importantes del país, y de la División para Cla-

do estos estudios, en la región occidental que desde Cabo Hojo Añasco se extiende al interior. Se estima que con

tes

lógico.

En

la actualidad, seis técnicos federales bajo la

dirección del señor R. C. Roberts, se encuentran adelantan-

-

.ÜEVISTA DE OBRAS PUBLICAS DE PUERTO RICO

902

una asignación final de $20,000 se cubrirá toda la Puerto Ricd en 1936. ¿

Qué

beneficios ofrece al pueblo

isla

de Puerto Rico,

de

el es-

—

Según progresa el trabajo en las zonas esvamos recibiendo mapas o informes preliminares sobre la extensión y descripción de los tipos de suelos en Oportunamente toda la información obtenida la región. en cada región se englobará en una publicación final conteniendo la clasificación, descripción y distribución én matudiadas,

de suelos en Puerto Rico. Como cada tipo de suelo tiene su correspondiente color en el maEl inforpa, se hace fácil su identificación y extensión. pas, de los varios tipos

me abarca

como base fundamental para

económico-agrícolas de las fincas pequeñas del digno de mención el caso específico de las reco-

los estudios

tudio edafológico?

Friynero.

utiliza el estudio edafológico

todos aquellos factores que tienen una relación

íntima sobre la formación de los suelos y sus pasibilidades agrícolas tales como el clima, topografía, profundidad del

Es

país.

mendaciones de suelos apropiados para riego, en el DisLa Hon, Cotrito Adicional para Riego de la Costa Sur. Sr. Luis A. al misión de Riego nombró asesores técnicos Serrano, Director de la Subestación Experimental de Isa^ hela, y al siiscribiente. Comentando el informe presenta-

do por

sobre

el

reconocimiento, a base

hecho en

el

campo durante

los asesores técnicos

del estudio edafológico,

el

mes

Comisión de Rie^

el Secretario de la Hon. nos escribe en carta fechada diciembre 5, 1934: ''La labor de los Técnicos ha sido estimada grandemente poi" los Miembros de la Comisión de Riego y ha servido de base

de octubre 1934, go,

para realizar una selección consciente de las. tierras que el Nuevo Distrito de Riego."

han de formar

:

suelo, geología, presencia

de sales nocivas a

la vegetación,

1

cosechas, erosión, etc.

Segundo.—

Beneficia a los técnicos agrícolas porque poder aconsejar a los agricultores sobre aqueEl llos problemas que afectan a los suelos y sus cosechas. técnico tiene al instante información precisa sobre los suelos

les facilita el

de la región de donde parte la consulta.

Aquellos resulta-

dos experimentales y observaciones de índole práctica-ecoKÓmiea obtenida en una región de suelos conocidos pueden

Las Estaciones Experi-

aplicarse a otros sitios similares.

mentales de la Universidad de P. R., del Gobierno Federal,

y de las Centrales Fajardo y Aguirre, llevan a cabo sus ex])erimentos de abonamiento, cultivos y variedades, a base

de la clasificación hecha en

el

estudio odafológico.

Mu-

chas centrales y colonos planean sus prácticas agrícolas a La División de Suelos y base del estudio odafológico.

Cosechas del Colegio de Agricultura y Artes Mecánicas de

Universidad de Puerto Rico, utilizan los datos del estudio edafológico en las cátedras de suelos y agronomía.

la

Tercero. ti[)0s

—

Ofrece

al agricultor

de suelos en su finca

y

le

información sobre

los

una información valiosa sobre finca que interesa comprar.

Cuarto.

— Facilita

Clarificación de la

Congreso Internacional Azucarero llevado a cabo en San Juan de Puerto Rico en marzo 1932. Copiamos del informe presentado por el Dr. W. W. C. jMoir a la Asociación de Técnicos x\zucareros del Ilawaii en octubre de 1932:

''Through the

el

hel]) of the

foUowed by the U. S. Department of Agriculture through the work of Dr. C. F. Marbut. This classification seems to one of the finest bases for land taxation yet put í'orward and on that point alone it reeommends itseli: lo This is a project that should be given US very highly. üul' most earnest consideration." í'urnish

La Sociedad Industrial y Agrícola de Punite-A-Pil

a base del estudio edafológico,

ins-

INYESTIG ACIÓN TÉCNICA:

una tasación más

juiciosa de la

fin-

La Sección de Agrología ha tenido

1

la

confección

de informes y estadísticas agrícolas, sociales, económicas, etc.

Es la base para el catastro de Puerto Rico. La Secla

Universidad de P. R.,

.su

cargo

el

si-

— Análisis

envía

— Es de inestimable valor para

a

guiente programa técnico:

Propiedad del Departamento de Te-

Economía Agrícola de

que dimos a sus

pectores agrícolas señores Jantet y Portal, en su inspección de estudios sobre la fase agrícola de la caña de azúcar.

el

químico de las muestras de su(^los <iue personal que tiene a su cargo el estudio edafológi-

co de Puerto Rico

ción de

re,

Uuadalupe, nos escribe en carta fechada febrero 4, 1935. reconociendo el valor inestimable de la información de sue-

valor de los suelos en la

sorería.

Quinto.

P>ureau of Chemistry and Soils

of the U. S. Department of Agriculture, the Insular Ex})eriment Station's soil department has been conducting a soil classification :survey along the lines of that started and

los,

ca para los efectos de contribución o hipotecas sobre la propieJad. De esto pueden dar fe la División de Tasación del naneo Federal de Baltimore en P. R., y la División para la

erior

brinda oportunidad de com-

parar su experiencia agronómica con otros agricultores que tienen suelos similares a los suyos. Presenta al comprador

—

Sirve de base para demostrar al mundo ex que estamos organizados agrícolamente sobre una ba^e sólida y científica al nivel de los últimos conocimientos sobre la agricultura científica. De esto pueden dar fé varios delegados técnicos que representaron a su país en el t^exto.

drenaje superficial y subterráneo, posibilidades de riego,

(1931-1935).

—

2.

Adaptación de métodos rápidos para reducir e^ tiempo que toman ciertas determinaciones en el proyecto i.

(1931 -33).

3.

— Estudios

de nitrificacióri en varios tipos de sue-

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO los

de Puerto Rico (1931 4.

-

1934).

¿

— Estudio del suelo en una plantación típica de

5.

—

la síliea

beneficios aporta al pueblo de

Puerto Rico, esos

estudios técnicos? ca-

Aparte de

(1933-1934).

fé.

Qué

903

los beneficios

de índole científica que esos

estudios de investigación aportan a la Ciencia Edafológiea

Estudios sbore la solubilidad de los fosfatos y en suelos situados a diferentes elevaciones. (1934-

podemos enumerar

los siguientes beneficios al

PUBLICACIONES

Primero.

—

Es de suma importancia süplementar

observaciones hechas en

Los resultados obtenidos en

el

proyecto II aparecen

publicados como sigue:

J.

el

las

estudio edafológico con infor-

mación química adecuada para obtener luz sobre la

defi-

ciencia o suficiencia de elementos químicos necesarios pa-

ra

Bonnet,

pueblo de

Puerto Rico.

A. and Villamil, F. A.

Research on

sliort-

ening time without affecting the accuracy of Dyer's modi-

el

crecimiento de las cosechas

;

])reseiieia

o ausencia de

acidez o alcalinidad excesiva que puede ser

i)er judicial

a

una cosecha determinada arastres interiores de los elementos químicos; relación del análisis ([uíniico del suelo ;

fied

metliod for determination in

soiLs,

of phosplioric acid,

lime and potash soluble in eitric acid solution.

Agrie, of P. R. 17 (4).

J.

Dept.

con

clima, etc.

el

1933.

Los resultados obtenidos en el proyecto III, sobre nide suelos, aparecerán en el número de abril, 1935 del *^ Journal of Agriculture of the University of

trificación

—

Segundo.

La adopción de métodos analíticos cortos y precisos economiza tiempo al personal técnico y dinero a la Institución.

P. 11.''

Un

informe sobre

los

datos analíticos de

los tipos

de

Terceío.

— Los estudios de

suelos en la costa norte de P. R. (proyecto I) ha sido en-

es

tregado a la División del Soil Survey, Washington, D. C,

ciertos tipos. (le suelos de

para ser insertado oportunamente en

la

Cuarto.

Los resultados obtenidos tu

¡ios

<roia

en. el

una plantación

del suelo en

los especialistas

el

nitrificación nos indican si

sulfato de amoníaco

como abono en

Puerto Rico.

publicación final

del estudio edafológico.

d oinformados a

conveniente usar

— Los estudios de

proyecto IV, sobre

(*«-

h)

sílice soluble

han

si-

se

hacen con

típica de café,

de café, en Fomento Agrí-

y Estación Experimental.

el

la solubilidad

de fosfatos y

en suelos situados a diferentes altitudes propósito de determinar un índice de rela-

ción entre los arrastres de estos ciernen ios de la altura a .sitios

niveles intermedios hasta los llanos.

(le

THE MAGNETITE DEPOSIS NEAR HÜMACAO, PUERTO By

R. J. Colonij,^' hoff,-\-

Member A. I. ^I. E., and Member A. I. M.

Associate

(New York

i\leeting,

Deposits of iron are widely scattered in the folded Cretaceous rocks and the associated igneous intrusives of Puerto Rico. Most of them are too small for commercial

development, but a few have aroused spme

economic

interest,

among them

scientific

and

the large body of residual

limonite at the west end of the island near

Mayaguez

1-6

and the mixed hematite and magnetite deposit on the southern slopes of the Sierrade Cayey, about four miles north of xYrroyo. 7-9

Neither of these orebodies has been devel-

oped. ñor hace investigations of the widely distributed deposita of magnetite,

currences of iron

which include all the remaining ocof economic eonsideration,

deserving

proceeded beyond the exploratory stage.

With the

possible exceptioíi of the

Arroyo, the magnetite

and

dioritic intrusives,

is

mixed deposit near

directly associated with andesitic

whioh invade the Cretaceous rock

//.

RICO

A. Meyer-

E.

February, 1935)

section,

iments,

and the bulk of is

it,

occurring in calcareous sed-

clearly of contact-replacement origin.

The small

on Río Portugués, north of Ponce, is found in a limestone band near its contact with an andesite dike. 10-lJ* Two deposits of undetermined valué flank the Utuado diorite batholith; one, on Monte Morales near Utuado, at the northern margin of the intrusión; the other, on the Alto de la ..Bandera between Adjuntas and Jayuya, along its Southern contact with the Cretaceous sedimentary section. dei)osit

By

far the largest series of magnetite deposita

San Lorenzo

is

periphe-

which outcrops over 180 square miles in southeastern Puerto Rico and extends to A band of stratified the neighboring island of Vieques. tuffs, shales and thin limestones roughly parallels the ral to the

diorite,

ncithern edge of this intrusivo, and contact phenomena are conspicuous along the entire length of the belt, a matter

"^i^^m^^^^T^n^^W -

'

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO

904 of 20 miles in Puerto Rico,

tensión into Viequcs

Within

this

is

and more than 50

and torrential wash of the normal ifneous materials on oxide, in comparison with the rapid partial decomposition every side. The phenomenon, indeed, is the usual one in Puerto Rico, where the rate of weathering and erosión is determined in large part by the relativo solubilities of the rock-forming minerals. For this reason the iron deposits generally produce conspicous topographic forms wherever they are exposed to the direct action of the atmosphere

if its ex-

taken into account.

contaet

zone there are more than 20

bodies of magnetite, all of which occur in the calcareous

and several of the deposits associated with the two modérate size and of They have attraeted some attention, excellent quality. and 30 years ago, shortly after the American oecupation of Puerto Rico, they were studied carefuUy; but plans made for their exploitation never materialized. Satisfaet-

strata,

thickest limestone horizons are of

and

Finally,

when

Rican mainland eral

ately coarse granitoid rock with the mineralogic composit-

W.

The quartz, however,

ion of quartz diorite.

component, and there are

many

is

a variable

places within the área of

outcrop in which the rock might more appropriately be classified

as

diorite.

Fettke has noted other variations,

wherein the normal plagioclase radorite

—becomes subordinate

—usually

andesine or lab-

to the accessory orthoclase,

and the rock assumes the aspect of a bornblende granite; or wherein augite takes the places of the typical dark Regional differentiation within broad mineralogic, yet relatively narrow chemical is thus a common feature of the intrusive, but the

brown-green hornblende.

District

Humacao, the

largest town in eastern Puerto Rico, is broad alluvial plain, which overlaps the northeastern córner of the San Lorenzo batholith. The iron crops out on the ridge that forms the southern boundary of the a

.

limits,

extreme variation that led to the differentiation of the

Humacao

iron deposit

is

distinctly exceptional to the gen-

eral range.

San Lorenzo Batholith.

—The

San Lorenzo batholith

about one mile south of the town and

less

than one-half mile west of the highway to Yabucoa.

It

forms the soútheastern shore lino of Puerto Rico, extend-

some 500 yd. south of the Roig sugar mili (Central Ejemplo) and is easily accessible from the cart roads that thread the adjacent cañe fields. The ridge rises abruptly, though somewhat irregularly, above the alluvium to an approximate elevation of 600 ft., and it ascends with similar abruptness above the higher rolling country to the south.

It strikes east and west, disappearing toward the east in the broadening alluvial plain, and merging about

from the mouth of Rio Humacao, on Vieques Passage, on the Caribbean. The front that faces the sea is broken by many alluvial re-entrants like the one. at Humacao, and its continuity is further interrupted by two series of sligtly younger granitoid rocks, which Fettke has" named, in the order of their intrusión, the Yabucao granite and the Patillas quartz monzonite. 14 13oth form a series of isolated stocks and apophyses situated at, or near, the margins of the batholith.

The gianito is cliaracterized by a*coarse texture and an almost complete absence of ferromagnesian components. In some local ities the quartz and oi'thoclase are micrographically

alluvial flat,

lies

a mile to the west with the elevated surface of the Sierra

de Cayey upland.

It

the

not, however,

is

upland, for

spurs in

its

it

a normal spur protruding from

differs

from the many neighboring its length.

The

comparativo isolation and in

ing

to the port of Patillas

intergrown; in others micVoperthitic intergrowths of orand plagioclase are found. There are no expos-

linear trend of its relatively level crest suggests a sediment-

thoclase

ary structural control such as characterizes hte magnetite

ures of Yabucoa granite in the immediate vicinity of the

hills in .

rougly rectangular in shape, with an

conformance with the orogenic structures of the CreThe intrusive itself is a médium to moder-

fairly

on

is

taceous rocks.

In connection with the investiagtion, a cursory field study was made 12 of a deposit south of Humacao at the eastern end of the belt, and, in contrast with the geographically associated bodies of magnetite, it was found to be a deposit of magmatic type, with f eatures of suf ficient interest to warrant a study apart from the routine classification accorded the other deposits.

Humacao

The

is

portion

axLs of elongation that trends northwest-southeast, in gen-

Bureau of Mines.

Geology of

Humacao

set-

deposit

of the batholithic intrusión that outcrops on the Puerto

pany changed hands, the project was allowed to lapse, and ha« never been revived.

In 1932, shortly after its organization, the Committee on the Mineral Resources of Puerto Rico made a brief examination of the more important magnetite deposits, with the cooperation of F.

general geologic

dominated by the San Lorenzo batholith. 13

the control of the com-

it

Ijee of the

—The

ting of the región surrounding the

ory royalties could not then be arranged with the property owners, and the engineering reports diverged widely on

tonnage estimates.

rain.

General Geologic Setting.

the sedimentary belt to the north and west.

suggestion

is

misleading, for the ridge, like the other hills

in the región,

rock, in

The

is

composed of

ma^ssive, granitoid igneous

which the elements of structural control are entireIts topographic prominence is due, none the differential weathering and erosión; for the ridge

ly lacking. less,

to

coincides with the areal limits of the magnetite,

prominence

reflects

the slow deeomposition

and

of the

its

iron

Humacao and

east,

ridge; the nearest

and another

to the north.

lie

three miles to the south

isolated exposure

is about four miles Occurrences of the quartz monzonilc are

considerably more remote, and for this reason the souc alaskite-aplite dikes which cut the rocks associated with tho magnetite deposit are believed to have been conneeted either

with the granitic phase of post-San Lorenzo inor with the gabbroie a.northosite-pyroxeniíe dif

ti-usion,

.

REVISTA DE OBRAS PUBLICAS DE PUERTO RICO an end-stage concentration residuum.

Intruded Stratigraphic Secti(m.\ The granitoid favaded a thick section of Upper Cretaeeous rocks, which axe l'erentiate series, as

—

They are exposed

clominantly voleanic in character. llie

that bound the Humacao and extend from this point

hills

north,

alluvial plain

in

on th^

tq the north coast of

the island without interruption, save for a few dioritic stoclís,

fluvial

section

approximately 9000

is

upward by a

tuffs at the base, foliowed

measured across the dip of the formations, is in most instances considerably less, and in one of the deposits in Barrio Collores de Piedras, the mineralized limestone i» separated from the iutrusive by as little as 600 or 700 ft. of tuff

ft.

Table

tuits, ash,

iíico.

Anciesite

15

and

mium üeveiopment

felsite

ñows and

siils

are

San Miguel

is

and

attained in the área lying immediat-

east of

In the neighborhood of siieeession

far

is

from

ciear.

per Cretaeeous voleanic vent,

Humacao

the stratigraphic

The locality is near an Upfrom which flows and shal-

iow intrusives were promiscuously introduced into the

During the closing stages of eruptive activity, vigorous folding and some thrust faulting occurred, which was immediately succeeded by the series of magmatic invasions already described.

Contact metamorphism obscured the sedimentary structures and converted the ñows and pyroclastic materials to an aggregate of chioritized rock, in which flow structure and undest-

section at every

Iron Ore

Las Piedras,

commonly

er granitoid intrusives.

horizon.

P. R. a

Fe203

FeO

ing the nature of the original materials

;

and certain

Only the lime-

of the shales have retained their ident-

and extensive siland mineralization of the former immediately north

despite the süicification of the latter

ication

üf the intrusivo contact.

Contact Ores. ion

is

—Although

the

Upper Cretaeeous

not directly related to the problem of the

magnetite,

sect-

Humacao

acquires pertinence because of the fact that

it

magnetic iron*ore was also introduced into the limestones along the northwestern and northeastem The sedimmargins of the San Lorenzo batholith. 16-19 entary members come into direct association with the (iiorite 011 these two fronts and, notwithstanding a rough

at several points

I)arallellism

between their strike and the trend of contact,

73.30 17.82

5.300

4.82

A1203

tr.

1.22

CaO

0.271

0.30

MgO

0.402

0.35

P205

0.056

0.054

S

0.008

0.03

tr.

0.00

C02 Cu IÍ20 (combined) II20 (free)

0.000

tr.

1.790

1.83

0.17

Metallic iron

99.998

99.894

66.05

65.17

a Analysis by Pattison and Stead, Middlesborough, England. b Analysis

by Edward Riley, London.

The magnetite

of contact origin makes its first appearrange of hills south of the Caguas-IIumacao highway about four miles east of Caguas, where it forma a broken chain of deposits stretching eastward for 12 miles along the border of the batholith.

At the easter;^ extremity of the magnetite belt, two parallel series have been formed in he two limestone horizons; but the more northerly band, best developed near the village of Torres, is comparatively remote from the intrusive, and the mineralization is si)otty and limited in extent. The eastérnmost of the contact deposits lies less than 4 miles due north of

ance

the

in the

Humacao

occurrence; and, despite radical genetic dif-

modes of origin and the inevitable cont-mineralogy and chemistry, the two types

ferences in their rasts in their

are clasely related in the time of their formation,

Unfortunately

impossible to compare

the two varieties chemically, for only

silicates,

including garnet, epidote, chlor-

amphibole, pyroxene and tale; but magnetite does not

appear, except in minor quantities wáth hematite, short

and

l)resumably they drew upon the same magmatic sources for their iron.

aggregate of

P. R. b

19.671

uow one formation, now another. Where the diorite im})inges upon the limestone, the latter has been altered to ite,

Ore near Juncos,

72.500

the intrusive cuts irregularly across the strike, penetrating

aií

Esperanza

but in some ca^es

oven the microscope cannot penétrate the metamorphic the formations have assumed.

:

Si02

royed fragmental textures supply occasional clues regard-

ity,

of Contact Ores

stratified series of

Humacao. Dikes and irregular mastíes of andesite porphyry cut the section but in turn are truncated by the San Lorenzo diorite and the youngely to the north

stones

— Analyses

It consists of

mtrecalatea with the stratified formations, and at one horizon they reach a thickness of 500 ft. or more. Their max-

ciisguises

1.

thick in this

5000 ft. of massive ashy shales and two interbedded limestone form-

part 01 Puerto

ations.

from the actual contact ín any of the orebodies.

The stratigraphic distance between iron and intrusive, as

of a mile

apophy«es and dikes, not to mention the reeent ísediments which locally bury them.

The

905

it

is

ses of the contact ore are available

analyses of the

Humacao

ore are partial (Table 2).

outstanding point of difference in the contact samples.

two complete analy(Table 1)^ and the

is

One

the abscnee of titanium

Pül?^ REVISTA DE OBRAS PUBLICAS DE PUERTO RICO

906

Table

— Analyses of Humacao Samples

2.

12

in responso to a

crest

14.49 0.49

12.66

FeO

0.11

MgO

0.14

CaO Na20

1.45

K20 H20

0.06

20.22

78.83

20.82

0.93

2.36

1.63

5.35

a R. B. Ellestad, analyst. alaskite-aplite dikes, cutting the rock associated with

the ore.

1.

Gabbroic anorthosite, base of magnetite ridge.

2.

Hornblendic gabbro, 150

3.

Hornblendic pyroxenite, 250

5.

Ore

Local

Guilles provide a few Prominent in the dark-hued and weathered l'resh exposures, from whielí satLsfactory specimens were gabbroic country rock are a few lenslike alaskite-aplite dikes, the freshness and light color of which provide a striking element of contrast to their more somber lithologic The dikes are irregular both in trend and in associates. thickness, but none of those seen exceeds 20 in. from wall to wall. Most of them exhibit gentle to modérate inclinations and severa! were observed to intersect.

ft.

above base of ridge. ft.

(To be continued)

above base of ridge.

Features,

Manuscript received at the

—The

Humacao

orebody

presumablj

lies

and the contact with the Cretaceous rocks a short distance beyond the base of the

ridge, buried-beneath the raile to

rises

Recent alluvium.

A

scant half

from the

fluvial debris, separated

from the

diorite ex-

are faced by a thin

band of altered

which preserve some vestige of an original sedimentary habit. Like all the Cretaceous strata immediately northeast of the batholith, they strike west-norhwest (N.57''W.) and dip moderaely rfortheastward into the broad synclinal fold th;at separates the massive igneous rocks of the Sierra de Cayey Tipland from the highly folded and compressed sediments. of the Luquillo Mountains.

The contact is also exposed on the outskirts of Humacao, on the northern side of the tuffs,

At the

which gíves

1

quartz.

is

C.

2

The Limonite Deposita of

Fettke and B. Hubbard:

R.

G. J. Mitchell:

Eico. Trans. A.

I.

M. E. (1919)

Survey of Porto Rico and the Virgin Islands (1922)

Síientific

3

L. A. Smith:

Trans. A. 4 1..

World Production and Eesources

M. E. (1931)

San Juan, P.

E., 1933.

H. A. Meyerhoff: Geology of Puerto Eico. Univ. of Puerto

Eico Mon. 1-B (1933) 134—136; 146—148.

6

H. A. Meyerhoff: Tron in Puerto Eico. Rcv de Obras Pú-

blicas do

Scientific

6,

Puerto Eico (1934) 11, 108—709.

C. E.

7

Fettke: Geology of the

Humacao

District,

Eeference of footiiote

9

H. A. Meyerhoff: Eeferences of footnote

4.

12

By W. D. Noble and H.

an excellent opportunity to study the progressive changes.

Quartz completely disappears, and augite becomes first an aecessory and then the dominant ferromagnesian mineral,

184.

5,

132;

footnote

707—708.

H. A. Meyerhoff: Eeference of footnote

these localities the diorite becomes in-

2,

•

8

G. J. Mitchell: Eeference of footnote

From both

Porto Eico.

Survey of Porto Eico and the Virgin Islands (1924)

11

creasingly gabbroii toward the iron deposit, and to the south the numerous exposures along the Yabucoa road off er

of Chromite.

387.

Committeo on Mineral Eesources of Puerto Eico Eept. No.

2-5.

5

I.

10

tint.

1,

292-294.

South

it

ridge,

61, 97.

Geology of the Ponce District, Porto Eico.

within 3|4 mile of the deposit, also normal, but it is notably deficient in

of the magnetite

the intrusive

a strong greenish

'

Mass.

Mayagüez Mesa, Porto

latter point, 1 1|4 miles north of the magnetite

chloritization,

Associate Professor of Geology, Smith College, Northamp-

-¡-

ton,

valley.

deposit, the quartz diorite is normal, save for conspicuous

New

York, N. Y.

the east, an isolated hill of metamorphosed tuff

posures on the Yabucoa road by 250 yd. of river sediments.

Still farther east the hills that fringe the Humacao plain

office of the Institute Oct. 23, 1934.

Associate Professor of Geology, Columbia University,

*

occupies a position cióse to the northern edge of the batholithic intrusive

and the steeper slope

produced has proved less hospitable to vegetation. The exposures have undergone considerable weathering, but not enough to obscure the identity of the minerals or the

magnetif erous pyroxenite, 400 f t, above base of ridge.

Geoíogic

greater,

is

ingly coarse toward the orebody.

0.56

:

floor

obtained.

Ti02

Soda

the relief between ridge

side, for in this direction

and valley

textural features of the intrusive, which becomes increas-

7.17

4.

to 34% modérate increase in the calcium content

the magnetite ridge the best exposures are on the

At

75.38

A1203 Fe203

26''

of the feldspar.

3

northern

Si02

from

to the albite twinning, likewise increase

Samples a

ex-

angles of the plagioclase, in sections perpendicular

'tinction

4

The

while the hornblende becomes less conspicuous.

2,

292.

6,

706.

A. Meyerhoff, respectively secretary

and geologist of the Committee.

13

C. E.

15

Fettke: Eeference of footnote

C. E. Fettke:

14.

H. A. Meyerhoff and

District,

Porto Eico.

Islands (1931)

2,

7,

Eeference of footnote I.

Scientific

268—269.

153—161.

7,

159—163.

F. Smith: Geology of the Fajardo

Survey of Porto Eico and the Virgin