Controls for Programmed Drill Control

In the case where the material is adhering to the drill pipe and coating the sides of the hole it is necessary to ream and clean the hole every 5 to 10 feet (1.5 to 3.0 m) to remove the offending material. It is also necessary to clean the drill periodically to remove the caked on material. This can be accomplished by removing the tool string from the hole and allowing the material to be scraped off by the guide bushing. It is important then, if the guide bushing is to be used to clean the tool string, that the bushing be kept in good repair.

In the case where the material is conglomerating into large pieces, these pieces fall back down to the bottom of the hole and are recycled through the bit to be broken up. If the amount of recycled material is too great it will accumulate at the bottom of the hole and restrict the main air stream. To keep this material at a minimum, clean the hole periodically. When hoisting the tool string, allow the material to be ground by the bit and fall to the bottom of the hole before cleaning the hole.

In the case where the material is caving from the sides of the hole, treat the formation as unconsolidated and drill according to the procedure detailed in this manual for unconsolidated material.

It is important when drilling through difficult formations to constantly monitor the machine and tool string. Allowing the tool string to become stuck is an expensive mistake and can be avoided by cautious drilling practices. Reaming and cleaning the hole may only take a few moments, but it could be the difference between an abandoned hole and tool string and a successfully completed hole.

ANGLE DRILLING

NOTE: When moving the mast for angle hole drilling on machines with mast lengths of 65 ft. or more, the drill pipe must be stored in the racks and the rotary head lowered to its lowest position.

Angle drilling follows the same general drilling procedures as vertical drilling. The main difference in the drilling procedures, besides the fact that the hole is at an angle, is the need to monitor the condition of the different systems more closely while angle drilling. The differences in the operating procedures for the different systems on the machine are limited to handling the tool string and raising and lowering the mast to the proper drilling angle.

When drilling an angle hole, monitoring of the system indicators such as the drilling air pressure, the rotary load and the machine vibration, becomes more critical than when drilling a vertical hole. The reason these monitors become more important is the fact that an angle hole will tend to wander downward as the hole is being drilled. This wandering is due to the drill steel assuming a natural camber as it is being extended past the guide bushing. This camber is unavoidable and becomes worse as the angle of the hole approaches 30 degrees.

The force of gravity continually acts upon the tool string causing it to bend downward. This downward bending is known as the camber of the drill pipe. This camber causes the hole to be drilled with a gradual bend in it. This causes the drill pipe to contact the side of the hole, increasing the load on the rotary motor. This also tends to inhibit the bailing of the hole since the cuttings are not flowing vertically. The flow of the bailing air (and suspended cuttings) must be diverted around the points that the drill pipe is resting on the side of the hole. This contributes to the increased air pressures needed to drill an angle hole. The vibration of the tool string will be increased while drilling at an angle, due to the tool string resting on the side of the hole, rather than on the bottom.

PROGRAMMED DRILL CONTROL DRILLING

PDC drilling is similar to normal drilling in that the machine must be positioned, leveled and set up manually by the operator. The actual drilling operation will be controlled by the automated system. To start the automated system use the following start-up sequence.

Controls for Programmed Drill Control

1. Make sure the hoist/pulldown rheostat and the rotary rheostat are in the “0” position.

2. Verify that the desired drilling depths, collaring depth, and wet hole depth have been set per PDC operating parameters screen on operator’s display terminal.

3. Place hoist/pulldown speed selector switch in the PULLDOWN position.

4. Place the operating mode selector switch in the DRILL position.

5. Press the drill/propel control ON pushbutton.

6. Place the compressor vent/drill switch in the DRILL position.

7. Verify on the operator’s display terminal that no PDC faults exist. If a fault exits, it must be cleared before the PDC control can be activated.

8. With the operator’s display screen shown in the operator’s display terminal, press the depth indicator reset pushbutton to reset the hole depth and bit depth indicators to zero.

9. Place hoist brake control in the RELEASE position.

10. On the operator’s display terminal with operator’s display showing, depress keypad button F5 to turn on PDC The readout above the F5 key will then read “PDC on.”

After the above start-up procedure has been initiated the automatic controls will take over the actual drilling of the hole. Water injection (if so equipped) will be shut off at preset depth. When the total depth of the hole is reached, as preset, the tool string will be automatically hoisted and when the bit approaches the top of the hole, the control will stop the bit, shut off the air and set the hoist brake.

If problems arise in the PDC functions, the system will have to be corrected by a qualified electrician. In most cases, if a malfunction occurs in the automated system, the automated system can be turned off and the drilling completed manually.

PREPARING TO MOVE

Once the hole has been completed and the tool string removed from the hole it is necessary to move the drill to the next hole location to prepare to drill the next hole. Preparing to move the drill consists of proper storage of the tool string, lowering the machine to the ground, and inspection of the machine and travel route prior to propelling.

To prepare the drill to move, proceed as follows:

1. Upon completion of the current hole, hoist the tool string from the hole. If using multiple pipe sections, remove and store all pipe necessary to remove the entire tool string from the hole. Turn off the dust control system and raise the dust curtains.

2. Clamp the stabilizer with the tool wrench to prevent movement of the tool string during propel.

CAUTION: Do not propel with the tool string in a position where it will be struck against the ground while propelling. Should the tool string hit the ground while propelling, damage to the machine and tool string will result.

3. Turn the automatic leveling switch to the RETRACT position to raise the jacks and lower the machine. Hold the switch in the RETRACT position until the jacks are fully retracted. Refer to the auto leveling screen on the operator’s display terminal to verify all four jacks are fully retracted.

NOTE: If the machine is to be lowered manually, refer to steps 4, 5 and 6 and operator’s display terminal screen auto leveling.

4. Using the manual leveling jack controls, lower the machine so that it remains level, but is touching the ground. Use the leveling jack controls in pairs (i.e. either both side controls, or both end controls simultaneously) to reduce the twisting loads on the drill frame.

5. Once the machine is touching the ground, it may be lowered completely. To lower the machine completely, first lower the uphill side or end of the machine to the ground, then lower the downhill side or end to the ground. It is important that the machine be lowered in stages to minimize both the angle of the machine and the bending stresses placed on the machine.

CAUTION: While manually lowering the machine to the ground it is imperative that the machine be kept as level as possible. It may be necessary to lower the machine in stages to keep it as level as possible.

6. Once the machine is completely lowered, retract the leveling jacks to the maximum retracted position.

NOTE: When manually lowering the machine be sure that the leveling jacks are fully retracted before propelling the machine. Propelling the machine with a leveling jack not fully retracted will result in serious damage to the jack and machine structures.

7. Inspect the machine, travel route as outlined in the Propelling topic in this manual. After completing the inspections the machine is ready to propel.

MACHINE SHUTDOWN

Shutting down the machine is necessary any time that the operator must leave the machine, either at the end of the shift, or for a period of time during the shift. Machine shut down is also necessary for most maintenance work to be performed.

Shutting down the machine is essentially the reverse of starting it up. The degree of storage work to be done is determined by the length of time the machine will be shut down. Shut down for a short period involves little extra work, while shutting the machine down for a lengthy period will involved considerable effort.

SHUTDOWN PROCEDURE

To shut down the machine, proceed as follows:

1. Complete the hole, if any, currently being drilled. If the hole is not completed before the machine is shut down, it will be necessary to abandon the hole and drill another in its place. Do not try to place the machine over an existing hole.

2. Remove the tool string from the hole. If multiple pipe sections are used, remove and store pipe sections as necessary to remove the entire tool string from the hole.

NOTE: Do not shut the machine down with the tool string in the hole. To do so may cause damage to the drill pipe and may lead to the abandonment of the tool string and the hole.

3. Determine the length of time the drill is to be idle. Refer to the appropriate storage topic in this manual for the degree to which the tool string must be disassembled. If necessary, disassemble and store the tool string at this time.

4. If possible lower the rotary drive unit to its lowest position and set the hoist brake. If the tool string is not to be removed, clamp the stabilizer with the tool wrench and set the hoist brake.

5. Following the procedures in the Preparing To Move topic in this manual, lower the drill to the ground. Place the leveling jack pads on the ground, but do not place any weight on them.

6. Shut off the main air compressor. Place all controls in the off or neutral position.

7. Go to the machinery house and turn off all breakers. If the machine is to be shut down for a short period of time and it is necessary to leave the lights on, it is permissible to leave the lighting breaker and lights on.

8. Inspect the machine for obvious damage or wear. Make note of any operating difficulties discovered while drilling and any problems discovered during this inspection. Report the difficulties to the appropriate personnel.

9. Close all doors and windows tightly.

SHORT TERM STORAGE

If the machine is to be shut down for more that 3 eight hour shifts, but less than 3 weeks, short term storage precautions are necessary. These precautions are necessary to insure that the machine is not damaged or does not deteriorate during the storage period.

Short term storage is primarily concerned with placing all components in a safe position and providing additional protective lubrication to normally lubricated components.

To store the machine for a maximum of 3 consecutive weeks, proceed as follows:

1. If not already done so previously, complete all shut down procedures as detailed in the Machine Shut Down topic in this manual. During the shut down procedure it is necessary to remove and store the complete tool string. Remove the bit from the stabilizer and store it in a protected place. Coat the bit with a suitable oil to prevent rusting while stored. As the drill pipe is being disassembled, clean and lubricate the threads on each end of the pipe before storing in the pipe racks.

2. Lower the rotary/pulldown unit to the lowest position and set the hoist brake. Inspect the rotary/pulldown unit for damage or wear and note any problems discovered. Cover the rotary and pulldown motors with waterproof tarps or covers. Raise the dust curtains. Retract the casing tong cylinder.

3. Check the oil level in the rotary/pulldown unit. Check the cases to see if there is water in the oil. If there is water in the cases, drain and refill the cases with suitable oil. If no water is present, fill the cases to the proper level.

4. Manually cycle the lube system and verify that all points on the mast are receiving lubricant. If the auto lube system is not functioning properly, repair or replace components as necessary.

5. Lower the leveling jacks until the jack pads are resting on the ground, but no machine weight is on them.

6. Inspect the air compressor for signs of wear or damage. Make note of any damage discovered.

7. If the air compressor motor is equipped with anti-condensation heaters, turn them on at this time. If the motor is not equipped with heaters, have a qualified electrician install heaters or a suitable substitute. Cover the motor with a waterproof tarp or cover.

8. Close and lock all electrical cabinet doors.

9. Fill the radiator to the top with the proper oil on machines equipped with screw compressors.

10. Manually cycle the auto lube system to verify that all points on the machine are receiving lubricant. Repair the system as necessary to lube all points.

11. Lube all manual lube points.

12. Clean the dust hoppers on the dust control system if required.

13. Close and lock all windows and doors.

LONG TERM STORAGE

Long term storage procedures are necessary any time the machine is to be left for a period exceeding 3 weeks. Long term storage includes all procedures necessary for short term storage, and depending on the situation, some additional precautions.

There are two procedures involved in long term storage of the drill, the choice of which depends upon whether the machine can be attended to while in storage. If the machine can be started and the majority of the machinery operated once a month during the storage period, much less protective work is necessary. If the machine must remain unattended, special precautions are necessary to prevent damage to the machine.

NOTE: If the machine is to be unattended during the storage procedure the procedures necessary to store the machine properly will take considerable time and restoring the machine to production will take even longer. Do not utilize the unattended long term storage procedure unless absolutely necessary.

ATTENDED LONG TERM STORAGE

The attended long term storage procedure combines the short term storage procedure with monthly start-up and running periods. To store the machine for a long period of time it is necessary to complete the procedures listed in the Short Term Storage topic in this manual. Then, once a month for the duration of the storage period, complete all start-up inspection and lubrication procedures listed in this manual and start the drill. Run all of the gear trains for 10-20 minutes to distribute the oil over the gears and bearings. Hoist and lower the rotary/pulldown unit the full length of the mast 4-6 times to distribute lubrication to the mast and rotary/pulldown unit components. Cycle the tool racks 2-3 times. Run the air compressor for 1 hour. Propel the drill at least 6 times the length of the machine. After running the machine components, follow the short term storage procedure once again and store the machine for another month. Repeat this procedure every month until the machine is returned to service.

UNATTENDED LONG TERM STORAGE

It is not within the scope of this manual to detail the procedures involved in the long term storage of a drill. These procedures will involve disassembly of the major units on the drill, duties that are not usually performed by operating personnel. Refer to the Mechanical Maintenance Manual for details concerning the long term storage of the machine.

The procedure listed here is an outline intended only to give a general idea of the effort involved in proper storage of the machine. To store the unattended machine for an extended period of time, proceed as follows:

1. Complete all short term storage procedures.

2. Remove the motors from the drill and store in a heated building.

3. Completely fill the rotary and pulldown gear cases with an approved oil. Both cases can be filled completely by adding the oil through the breather openings. Remove all water from the cases.

4. Loosen the guide rollers on the rotary/pulldown unit frame to provide one-half inch clearance between the rollers and the mast.

5. Remove the auxiliary winch line.

6. Cover the rotary gear case and hoist/pulldown gear case with a waterproof tarp.

7. Remove the air compressor from the machine and store in an attended heated building.

8. Close and completely seal all electrical cabinets.

9. Close and completely seal the operator’s cab.

10. Close and completely seal the machinery house. Completely seal the filter fan unit.

11. Completely drain the compressor coolant system.

12. Propel the machine onto blocks to prevent the crawler belts from rusting. Coat the entire crawler belts with a rust preventative oil. Coat the propel chains with a rust preventative oil.

13. Block the leveling jacks in the full retracted position.

14. Manually grease every lube point (including auto lube points).

TOOL RECOVERY

Normally the drill tools are always either connected to the rotary drive unit or are held by the tool wrench. Mistakes, however, do happen and the drill tools may be dropped down the hole. Tool recovery (or tool fishing) is the procedure used to recover these tools.

There are two situations where the tool recovery procedures are necessary and each situation dictates the procedure to be used. The first situation is when the tools have been uncoupled and have fallen below the guide bushing. It is possible in this situation to recover the tool string and, if no damage was done, return to drilling. The other situation is where the drill pipe has broken and has either fallen below the guide bushing or cannot be handled normally.

If the tools have uncoupled and the upper end of the tool string is still above the guide bushing, recouple the tools as would normally be done for tool joint make-up. Clamp the tool string with the tool wrench to aid in making the joint. When the tools are coupled, remove the tool string from the hole, remove the bit and turn the main air on momentarily to clean the inside of the drill pipe. Clean and reinstall the bit and return to drilling.