Late December last year I began digging a 6' x 6' prospect shaft about 100' downstream from the original Cobb prospect shaft. Armed with a 30 lb electric jack hammer, a couple of shovels and my nifty 1/2 size home made "Fairbanks self dumping bucket" system I worked my way down through frozen muck and eventually a 10' gravel layer to bed rock at 62'. On my way down I encountered layers of tangled branches and trees up to 6" in diameter. After 40+ feet I hit fine sand and scattered patches of gravel, fossil bone fragments, then complete bones. I was anticipating these finds but the excitement of actually finding them was intense. The first chunk of mammoth tusk nearly put me over the top. Progressing downward, the bones became less frequent and the pay gravel more dense. I had been told that a jack hammer would be ineffective in frozen gravel. Good I don't listen to everything I hear; it busted up almost as easy as the muck. The gravel graded into fractured and decomposed bed rock and I knew I had finally reached my goal...10 months after starting the project. Before freeze up I was able to wash 5 yards of pay and the result was encouraging. I'll have to wait till late spring to resume processing what I brought up before and what I can hoist this winter.
Now it's late November and all is solidly frozen above as well as below ground. Since bottoming out in the shaft I've been devoting most of my time to upgrades above the shaft in preparation for winter work. Also I had to take a part time job in town to help pay for the added expense of moving to a small cabin also in Fairbanks. What little time I've been able to devote to underground efforts have been to expand my working space. On the way down I managed to increase the dimensions of the shaft from 6' x 6' to over 7' square. The plan is to continue out to 10' square before I begin pushing the drifts across the valley.
Jack hammering straight down is relatively easy compared to working horizontally and even vertically. Sufficient pressure is difficult to exert out of position so I began working on ideas to free the gravel other than by the traditional steaming or blasting to reduce the great amount of physical labor involved with jack hammering. Suffice it to say, I'm making good progress in those efforts. I'll report on this process in months to come.