Geotechnical drilling, what we used to call mineral exploration, or just mineral ex, is quite different from normal water well drilling. Sure, we drill a hole in the ground, but the methods and objectives are very different. Usually, it’s done in hard rock, but instead of a hammer making fine cuttings, most of them are cored, so the geologist can see what the formation looks like in situ. Core bits require cooling and lubrication, so fluid circulation is required. Usually, the pump is quite different than the normal pump on a water well rig. High pressure is required to overcome friction in the pipe and core barrel, and large volumes are not usually called for, so a small, high-pressure triplex pump is used. A lot of the time, the driller won’t even get returns to surface. As long as the bit stays cool, it’ll drill. Outside cuttings are chased into vugs, or cracks in the rock.
I was once on a job in central Slovakia, in the largest volcanic caldera in Europe. Not as big as the Yellowstone caldera, but still about 25 miles across. The customer had bought a mineral lease on most of the area, and hired us to explore and find what he had bought! We had a new track-mounted, Korean rig that could angle drill, and a portable mud system (that I built), so we could go just about anywhere and drill just about anything, which was good because the geologists just marked dots on the map and expected us to drill there. They never went to look at site conditions, and part of the contract stipulated that the pristine forest be disturbed as little as possible. These constraints made for some interesting locations.
Crew accommodations were interesting to say the least. My boss didn’t go cheap on them. In one place we stayed in a medieval castle. I was rigged up for tourist accommodations and he rented the whole place for the 20 or so of us. There were more staff than guests. Dinner was served in the great hall. Great food. Everyone had a private room. We would leave our coveralls and work boots outside the door at night, and in the morning, our clothes would be clean and our boots polished. First time I ever had polished steel toes. Every day.
When we worked on the other side of the caldera. We stayed in one of the more interesting places I have ever seen. It was a power-house! From the outside, it looked like a large, central European house perched over a small river with a dam and a large pond outside. One man lived there. He owned the place and produced hydroelectric power for about 30 farms in the valley. There was about a 20-foot drop between the pond and the tail water, and the man who built it ran the water in, under the kitchen floor and into two turbines that were actually turbine pump bowls. The drive shafts came up to floor level and the generators were actually in the living room! It was a big living room with an overhead crane for maintenance. The place was kind of noisy, but very interesting, and the old man who ran it was very proud of his equipment. He would sit in his easy chair and watch a TV that you couldn’t hear, and occasionally get up and tighten the packing on the head shaft, or look at his gauges. Good cook, too.
The drilling we did, and the cores that we recovered, amazed us every day. I don’t know if the things we found were of commercial grade, which was for the bean counters to determine, but we saw gold, silver, copper, tin, lead and almost all the common hard rock minerals within a few miles of each other — sometimes in the same hole.
When we got to the far eastern side of the lease, near the border to a huge national park, it was discovered that there was some uranium in our cores. Naturally, this attracted the attention of the government, and they hired us to go into the park and core for uranium. Slovakia has commercial quantities of uranium, so they have the infrastructure and an army of government employees to oversee it. Since they have no reactors, nor nuclear bombs, the uranium they produce is sold on the open market. An interesting quirk in the law there: They will not sell any uranium to any country that has nuclear weapons, so the U.S., Russia and all the rest are not on the customer list. They sell to places like Brazil, Argentina and others that generate power with it.
The last hole we drilled for them was up a very steep trail, about a mile up from the road. We had to winch most of the equipment up there. Being a government supervised operation, they had their own inspectors and geologists with us at all times. Most of these guys were young engineers that took themselves very seriously. Whenever we would recover a core, they would hover around and look worried until we pushed it out of the core barrel, and then they would take possession. Much paperwork and multiple signatures were required. They would take the core over to a small area they had staked out and mark it and examine it with a Geiger counter, and fill out more paperwork. They guarded the cores jealously. We were not allowed to go anywhere near them, even though we were the ones who recovered them.
This didn’t make my boss too happy, not being trusted and all, and when the job ended, and we winched our rig and equipment back down the mountain. Then, karma came calling. The kids, as we called them, asked if we could load up their cores, and haul them down the mountain for them, after giving us dirty looks and ominous gestures for weeks. My boss explained that those cores now belonged to them and we were not allowed to touch them, and that, NO, we wouldn’t haul them. There were about 3,000 meters of 4-inch, solid granite cores. They are probably still packing them down the mountain to this day!
For more Wayne Nash columns, visit www.thedriller.com/wayne.