Friday, October 28, 2011

Mining the Christine Marie: Abrasive Rock

The two host rocks separate.
The jasper on the Christine Marie claim is in a steep rock slope about halfway down the canyon from the rim above. The host rock is labeled a welded tuff, and extends from the slope of the hill up past the cliff above to the pinnacle on the Amy Ellen claim; a distance of around 200 yards. The jasper formed in cracks in the tuff before it was in its present position. The entire hillside is a mixture of very large rocks (2-10 tons) and millions of small ones (1/2-5 pounds).

This rock is very abrasive. Because of the rock’s abrasiveness the rocks do not fall easily, but cling to each other. This quality contributes to the steepness of the area by not allowing rocks to erode downhill as fast. To illustrate this, it is possible to take two flat pieces of this welded tuff, place one on top of the other and tilt the pair of rocks almost 80 degrees before the top rock will fall off. Try this with most other rocks and the top rock will start to slide off with a tilt of a little over 45 degree
Gene holding the two pieces of abrasive rock.

The jasper in this deposit is scarce, but very good. A lot of rock must be carefully moved to collect a small amount of jasper. The abrasiveness of the rock takes a toll on your gear, as well. There were many days where a new pair of gloves in the morning would have one or two holes in the fingers by late afternoon. Using duct tape on your fingers was a common practice used to get more use out of a pair of gloves, or a little less wear on your fingers. I learned to buy a new pair of boots before I came out to the mine because a pair of boots lasts about a month working in this rock. I always use steel toed boots to protect my feet. After a month of mining Morrisonite, the leather would be worn off the toes of the boots revealing the scratched, shiny metal underneath.

Notice how tilted the rocks are, and they still stay together.
One very good thing about working in this rock was that it would always warn you when it was about to fall. Unlike other rock slopes which can give way with no warning, this rock will talk to you before it falls or gives way. The abrasiveness of the rock holds the pieces together until gravity becomes too much and you will start to hear small sounds. Soft sounding “ticks” and small creaks can be heard once in a while, and then more frequently. Through experience you come to understand when to get out of the hole you are working in and wait for the rock to cave in or get out of your hole and start the rock slide yourself, thus making it safe to work again.

Friday, October 14, 2011

Mining Morrisonite: Christine Marie – CASE 850

The levers.
Operating a CASE 850 frontend loader is about as different from operating an old D-4 Dozer as it gets. While operating the dozer, I was constantly moving my arms, pulling levers to steer the machine. The CASE could be driven with just my left hand! There were three little levers right next to each other on a pedestal between my legs as I sat on the machine. The right lever, which can be moved with one finger, provides power to the right track in low gear if pulled back and high gear if pushed forward. The left lever does the same for the left track. The middle lever moves the machine forward if pushed forward and backward if pulled back. The middle position for each lever is neutral.
Gene and the CASE-850 hard at work.

The machine can be turned to the right two different ways. By placing the left track in high gear and the right track in low gear, the left track will move forward faster than the right track turning the machine to the right. This is an advantage for the CASE because most other machines turn by subtracting (breaking) power to one track or the other rather than having power to both tracks. The CASE can also be turned to the right by putting the left track in high or low and leaving the right track in neutral. The weight of the machine will hold the right track in place while the left track drives forward, turning the machine to the right.

Gene, the happy miner.
Because the CASE 850 has a torque converter transmission, the tracks are free to roll if there is no power directed to them. But if turning right on a steep hill by providing power to the left track and leaving the right track in neutral, the machine can actually turn to the left instead. The free-wheeling right track can outrun the powered left track and move the machine to the left rather than right. This can make for some interesting times while operating on steep ground. Also it is very important not to allow the engine to stall; this will result in a 10 ton machine rolling down a hill with nothing to stop it but the bottom of a steep ravine. 

The CASE 850 does have breaks, but they are a joke. They were designed using old car parts and never worked well. I almost never used them. If I was driving the machine forward and needed to stop it, I could easily put the machine in reverse and accelerate. This machine had a foot-operated accelerator just like a car. The automatic transmission or torque converter would slow the machine to a stop and start moving backward. 

A view of the levers from the seat.
All controls which move the machine can be operated with the left hand on the three levers freeing the right hand to operate the bucket. A machine which can pick up rock and put it where you wanted it, is a vast mining improvement over a machine that can only push things around. Jake’s suggestion that I buy the CASE 850 greatly improved my success mining the Christine Marie.