Field and CPL Updates
Update provided by Jay Johnson, ICDS
Activity: DISC Drill Test - Summit Greenland
Weather Conditions: Temperature range -21°:C to -8°:C, wind 3-30 knots
ICDS Personnel on Site:
Activities During Period:
Drilling - This week we drilled a total of 160.311 meter. The bore hole depth is 618.85 meters. The average core length was 2.42 meters. The longest core drilled in one trip was 2.67 meters. Three cores were drilled with an average length of 4.155 meters from a depth of 458.54 to 470.91 meters. They were drilled by removing the core dogs for first 2 meter run and then replacing them for the second run. All three cores were pushed from the core barrel in one piece. Drilling cores with this method is more difficult and risky than drilling a single 4 meter core because the drill must be rethreaded over the first 2 meter core. The drilling of these three cores has proved the DISC drill is capable of retrieving high quality 4 meter cores in one piece. These cores went to NICL for the ductile ice acceptance test. All cores drilled this week have been made available to NICL for setup and testing of their equipment.
Cutter head and core barrel - I modified one of the cutter heads by opening up the cutter windows. We wanted to see what effects changing the fluid flow around the cutters would have on drilling. After several drill runs it was concluded that we saw no change in core length, quality, or chip collection. Up until now we have been drilling without the first core sleeve in the core barrel. The core sleeves started about 31 cm up from the cutters. We tried adding the first sleeve which extends down to the face of the cutter and found it caused the cutter head to plug with chips within the first .4 meters of coring. With the latest configuration we have core sleeves down to with in 6.3 cm of the cutters and this is working well. Another modification I did was to add more relief to the inside edge of the cutters (the edge of the cutter that is closest to the core). The added relief eliminated a white colored 45 degree helix pattern we were seeing on the outside of the cores and also reduced the quantity of small surface fractures. Over the past week we also tested the three different height shoes (.6 degree, .8 degree, and 1.2 degree) we have for the cutter head. All cores drilled during the shoe tests were of very similar quality. The only visible difference was the change in pitch. Our preferred drilling parameters are the cutter set at 80 rpm with a starting feed rate of 9.5 mm/s and the pump running at 2100-2300 rpm. This sets a good balance between motor current draws and drilling speed.
Winch Test - As I have written over the past weeks, when we run the winch at .7 m/s the level wind drive faults out sporadically. With technical support from Madison, Paul confirmed controller parameters and running feed back data. Everything looked to be set and operating as it should, yet every now and then the system would fault. On Friday we ran tests with the winch running at higher speeds to monitor how the level wind was tracking the winch drum. We ran the winch tripping down at speeds up to 1.4 m/s and tripping up at speeds up to 2.0 m/s. No faults were incurred. Depending on which way the level wind is being loaded the carriage bounces around a bit upon winch start up. The lead screw also makes creaking noises (ie. Stick-slip between the screw and nut) when the level wind changes direction despite the screw having proper lubrication. This is due to the pore design of the level wind section. These symptoms will most likely get worse with time. Other than these observations the winch ran smoothly.
Instrument section K - We have been running instrument section K all week with out any problems until we did the winch tests. After concluding the winch tests we went to do a drill run and found the pump motor controller wouldn't talk to the computer. The cutter motor was working fine. After several attempts to establish communication the drill was pulled up and the instrument section was removed. Upon removal of the bulk heads we found four out of five of the Glenair electrical feed thoroughs were leaking internally. The inside of the instrument section was completely wet with Isopar-K. I would guess an ounce or two of fluid had gotten in. Worse yet there was visible signs and smells of burnt electrical components. Nicolai removed the electronics and did a full diagnosis. He found the OVP circuit of the MPS and the filter capacitors on the cutter motor driver board had destructively failed. He determined that the electronic failures were not due to the Isopar-K leak but rather the drilling fluid back driving the pump during the during the winch tests. The pump motor effectively turned into a generator back feeding power into and overloading its control circuits. Nicolai is currently trying to salvage, clean, and repair this instrument section.
Instrument section J - Nicolai found a similar problem with this instrument section as we had with K. The P3 connector on the pump motor driver board had bad solder joints. Upon putting it back in service we found one of the micro controllers doesn't always like to boot up. We have only done two drill runs with it so far and both times it took a few attempts to get the controller to come up. So far once running the micro controller has stayed on line.
Shift work - This was the last week of working two shifts. Given our current drilling depth, current goal of 730 meters, and quantity of drilling fluid left, I decided to drop second shift so we don't run out of work before the DV visit during the week of July 9th.
Update provided by Geoff Hargreaves, NICL
Activity: NICL Greenland Test
Weather Conditions: Very warm towards the end of the week!
NICL Personnel on Site: Geogg Hargreaves, Brian Bencivengo
Activities During Period:
- Fired up computers and played with database, moved one computer into core handling tent for testing, shut others off.
- Found computer in case runs hot, so add a top vent hole, which cooled it off.
- Found computer in case runs hot, so add a top vent hole, which cooled it off.
- Found difficulties with database, Not touch screen friendly, no touch pad on screen for number entry. While there is a validation check for core length within a run, there is no validation between runs for depths.
- Brian building 2m V trays, Geoff started modifying the database to be more touch screen friendly, and add a keypad to each data entry screen.
- Brian checked ice quality as it was unloaded from barrel. The micro-cracks, although orientated differently are still present. The ice is progressively becoming brittle.
- Geoff continued to modify database, trying to simplify screens for data entry. Eric has done a good job of database development, but we need to make screens simpler, buttons larger, field boxes larger. Brian worked on making 2m V trays, rearranged part of weatherport to allow for another table. Brian set up computer stand, did not mount computer due to database problems.
- Started discussions with Camp manager for a larger hole dug for full size drying booth test.
- Geoff spent aprox. 1/2 day on the database putting keypads into the last of the data entry screens and making items he had added work with each screen. Brian made more V trays in the morning. In the afternoon we tested the small saw and found that it is not mounted correctly for a direct replacement with out changing the height of the support table. Also, this saw runs at a very slow cutting speed. Removed the little saw and put the big one back on and worked to stiffen the base of the large cut saw.
- Due to out of balance drive wheels, the saw vibrates a great deal. The MK table we had built for it is not stout enough for this saw. We added braces to stiffen and prevent racking. Stood the table upon 2x4's to spread the load of the saw across several floor plates (plywood floor over joists on snow flexes with the load), this decreased floor flexing, which contributed to the vibration.
- Continued with re-leveling the big saw and screwing it down to the floor.
- Moved the linear actuator from the rear (the arm flexed too much) to the front, which also helped decrease vibration. We found the cause of the vibration to be the drive and idler wheels. While they run true, they are not balanced. We put the heaviest parts of the wheels in opposition and that also helped decrease the vibration. However there is still enough lateral vibration to cause core to break. Found the linear actuator to be slow, voltage was only 18 volts out of the power supply (should be 24V).
- One core had a broken bottom end and all but the bottom end went through the FED. The bottom jammed at the entrance of the FED, the top was taken off of the FED and the pieces were fed through by hand. Other cores that had breaks mid core have had no problems. After this, the drill broke down possibly due to a "back EMF" caused by running the winch rapidly. ICDS shut down to work on this problem.
- Finished mounting the linear actuator to the front of the saw. We have had to borrow MK system components and materials from ICDS to make various changes to our saw. Tried to adjust the voltage on the power supply, it quit. Opened it up to find one leg of the potentiometer that adjusts the voltage has a broken leg. Tried to repair, but did not finish, quit, annoyed and cold, went to dinner. Talked with Jack Dibb re. digging another hole for our drying booth test. He saw no problem with this, but suggested it would be a good idea to request and extension to our original SIP from the SUMMIT SCO. Wrote extension request.
- Worked on power supply and got it working, tested cutting ability on a piece of ice we had in the tray (melting slowly, since the temp was 48F in our tent). Worked on the database. Wrote weekly report
Comments (Problems, Concerns, Recommendations, etc.):
- Saw table must be more robust and stable. We have semi-stabilized with cross braces, but need a more robust table.
- Saw table needs easier adjustments. Present adjustable legs are insufficient, and dangerous, had table and saw fall over because one leg was not tight enough and Geoff loosened a leg on the same side to try to even up a wobble, and the whole shebang + roller table fell over onto Brian, NO INJURIES, but scared the willies out of all of us.
- The floor under the saw must be stabilized and less rocky (the floor that we currently have is made of plywood over joists on snow, and not only uneven, but unstable.)
- Saw drive and idler wheels must be balanced, they cause a great deal of vibration.
- If we use a linear actuator, it must be faster in the up direction.
- When cutting with big saw, there is slush/meltwater buildup on the entry side of the ice core. I am guessing this caused by the blade heating up as it goes through the two 45 degree twisting roller guides at a higher rate of speed than what is normal for the saw, since NICL considerably increased the blade speed. We don't have an immediate solution to this one.
- We need a small shop vacuum to be able to clean up small messes, we don't want to contaminate R2D2 (the explosion proof "shop vacuum" used with the FED) with metal shaving and wood dust etc.
- Wooden V-trays have too many anomalies in their design to allow synchronous transitions. With each new tray, NICL must readjust the saw, roller track, saw table, Aluminum tray, or some variation of the above. As well, each tray is warped in such a way that once ice is upon it fracturing is possible. NICL foresees many problems when using the wooden v-trays on brittle ice.
- Add validation checks across runs to make sure depths are consistent.
- Make all screens more touch screen friendly, bigger field boxes for easier field selection, NO sliders, simplify screens, many simple screens are preferable to a few complex screens.
- Titles for data entry screens will decrease ambiguity of what screen is being read.
- Find a way to eliminate both keyboard as well as mouse, ie, make onscreen keyboard and keypad for every entry screen.
- NICL sees the validity of cordless power tools. These have proven to be invaluable while working in our confined area (no tripping over extension cords, able to work outside, etc.). Thank you ICDS!
- NICL will need another basement in order to store core from acceptance tests as well as for drying booth testing.
- Temperatures for the last 3 days have been above freezing in the Core handling tent.
- Saturday and Sunday the temp was 48F. As a result, NICL believes that many of these tests will have skewed results.
- Just before dinner, ICDS pushed an excellent (no breaks) core out from about 600 m and it was crackling as it went into the plastic covered tray, a few minutes later it popped a diagonal break, after dinner, it had several cracks and spalls in it.