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Small Bedrock Bonanza

I was on a prospecting walkabout one midsummer day. The sky, a perfect cobalt blue was accompanied by the deep warmth of a blazing sun. Happy to get a break from several days of either cold drizzle or pounding rain, I checked out some old workings near a creek almost strangled by thick stands of Alder, deep green ranks of horse-tails, clumps of butter-cups, and tall meadow grasses.

The heat from the sun made it humid by the little creek, with no breeze to lift it. However, this combination made things perfect for an attack by a living wall of black flies, mosquitoes, and no-seeums. The air was so thick with them that I was forced to breathe through my nose and keep my mouth closed or I got a mouthful of flying protein! So, I whipped out my can of nuclear grade Deet and gave myself a solid spray. That done, the flies backed off and spun angrily about four inches out.

With enough bug paste in my mouth to last a lifetime, I cut up the creek bank into the much cooler darkness of a stand of hundred-year-old pine, the floor carpeted with freshly dewed ferns. I wound along through the timber, then turned parallel to the creek, heading about thirty feet upslope. At this elevation, there was a gentle breeze blowing that sent the bugs back to the creek.

The signs of old 1800’s workings were everywhere, with more modern excavations from the 1930’s. Exploring the old diggings, I found some exposed bedrock. It appeared that a small operation had stripped off about ten feet of yellowish boulder clay (stubborn clay and boulders dumped by glaciers) to expose an old channel tight on bedrock, one that cut back under the steeply rising boulder clay.

The cut was about twenty feet wide and about sixty feet long. It ended where the shoulder of the mountain thrust through at a place where the old channel took a sharp turn to dive back under about fifty feet of boulder clay. Clearly, it was far too much overburden for a small 1930’s operation to work.

I headed back to the exposed bedrock, dropped my pack, and pulled out my sniping tools and my gold pan.

I scraped around for any low spots that still held accumulations of original channel, containing small tightly packed river stones and dark-gray clay. I found some spots, cleaned them out, then headed to the creek to pan: almost no black sand, and no gold. I went back up to the workings and sat on a flat boulder. I took a long look at the topography. I noticed a spot where the bedrock rose sharply from the exposed sheet, then levelled off as it ran back under the boulder clay. I also noticed the bedrock located there was covered with two feet or so of clay slump.

Personally, I'd rather not dig if there's good exposed bedrock to work, but as the bedrock was unproductive, I surrendered and took my shovel and cleared a spot about four feet square. The bedrock here was all uneven, with lots of irregular little pockets. I cleaned a few out but got no satisfying results. Ready to leave, I hesitated, then dug under the boulder clay where the bedrock started to dip beneath it. I was surprised to see a cumulative drop of about a foot, but then it leveled off again. However, what interested me most was the composition of the material between the boulder clay and the bedrock in the pocket I’d uncovered. It was a gray colored sand atop a packed clay and rock mixture that contained small pebbles. That material really lit me up! In that area, it’s the kind of stuff anyone hopes to find. It's a sure sign of virgin ground.

What I had opened up to find the pocket was the bottom edge of the face, the portion exposed in the 1930’s. As a result, I was working intact ancient channel, possible placer countless years in the waiting. The series of irregular holes I'd cleaned right before hitting the drop-off were encouraging. However, this was a bigger pocket, about a foot across, a great looking trap. Pumped now, I cleared several pans of material to bedrock, then lugged them to the creek. No gold! What was going on here? Everything was so perfect. I pulled out some lunch and took time to reflect.

After eating, I went back to examine the hole. The air had dried the moisture from the bedrock, and I was staring at some reddish bedrock, not black-colored slate like the other bedrock behind me. Regardless, that was not what caught my attention. The bottom of the hole was laced with what looked like a network of blood vessels, twisting purple veins sharply contrasted against the red rock. Never before had I seen such a geological result. Nevertheless, I took a screwdriver and scraped at the veins. Shockingly, they were nowhere near as hard as the rock. In fact, they were more like a purple clay, and I soon discerned they were sealing cracks in the bedrock! On fire, I dug and scraped and soon had about a tablespoon of material.

I hurriedly took it to the creek and sunk the pan. The bugs were back, but I didn't care. The blood I’d donate to get a look at something so interesting was insignificant. As I mashed the material under the water against the bottom of the pan, the water turned an ugly purple color. The panning water had been crystal clear, but I couldn't see the bottom of my green pan. I sunk the pan flat in the creek and continued to let the creek carry off the discolored water. The water was now clear, and in the crease were very dark, heavily stained BB-sized stones. This was something new. I tipped the pan back to pick out some of the stones and saw the yellow flash of sassy gold emerge. There among the black BB’s were three chunky pickers, no fine gold whatsoever.

I flew back to the hole. I gouged as far as I could into the cracks, but very little material remained. I took out an awl and probed the crevices and was rewarded with a soft resistance at the junction of two veins. I pushed harder and the awl dropped three inches. I twisted the probe in the opening, and it spun in an ever-widening circle. Having found a bedrock pocket that was fed by those gold-bearing crevices, I worked with a chisel and opened a hole to get the bent handle of a spoon inside. In this manner, I gouged around and drug out about three tablespoons of wet, purplish clay packed mixed with sand, and small stones. With no material left in the hole, I don't think my feet ever touched the ground on the way back to the creek.

I got the same result as earlier, a cloud of heavily dyed material from ancient, oxidized sediments. The stones were slightly larger than BB's when I could finally see them in the crease, but this time the gold poked through nicely! A clutch of pickers in the quarter to half gram range, and every piece was rugged with character.

I never found any more gold at that place as the bedrock dipped again, stopping me from chasing it under the boulder clay. But I did walk away with over ten grams of beautiful gold from my small, bedrock bonanza.

All the best,

Lanny