Thursday, September 15, 2022

Placer gold part one

I'm still chewing through the photo editing. I can only do it for so long before my eyes go bonkers and I start wondering what the heck I'm doing. Still to edit is the early morning of aurora photos, and our last day in Whitehorse, where most of the photos are from the YWP. 

One of the trip highlights was gold mining. In previous trips we had visited Dredge 4 and panned for gold at Claim 33. However, we hadn't been able to go inside the dredge until now. It's a pretty amazing machine. They're still working on it, and we couldn't go everywhere inside, but what we got was a start.

From a photographic point of view, the light inside is amazing, if somewhat dim. I used the big 14mm lens and pretty well shot wide open, so there will be some edge distortion. It would have been lovely to mount the film camera on a tripod and get photos that way, but there wasn't that much time. 

I suppose I should back up a bit and tell you what's special about placer gold. It exists as grains and nuggets in alluvial gravel from stream beds. The nuggets are what got everyone excited back in the day and triggered the gold rush, but the grains are where the money is. Sort of.

A grain of gold is tiny, and heavy compared to the gravel and sand it's embedded in. Swoosh it with water to wash away the lighter stuff and you're left with gold. That's what placer mining is, to sift through huge volumes of gravel and sand to find the few grains of gold, as efficiently as possible. Consider the layer of gravel and sand that contains that gold is just above the bedrock, and below a layer of permafrost, and might be 30 or 40 feet down. 

The dredge scooped up the gravel (after the permafrost was thawed) and ran 14,000 M3 per day through a process to separate the gold from everything else. Something I hadn't known is that this machine was noisy, and everybody that worked on or near it was probably functionally deaf in short order. The buckets are tough metal holding hundred of kilos of soil, mounted on a metal chain, with metal pins joining everything together, and there was no lubrication because it would tend to trap the gold. So imagine the sound of the big engine driving the chain, the scraping sound as the buckets gouged out the gravel, the rocks being dumped into a huge turning metal cylinder to do the first stage of separation, and of course back in the day there was no legislation about noise levels or hearing protection. The guides said it could be heard operating as far away as Dawson, about 15 Km away.

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Next up is an actual working gold mine. Stay tuned.

Of the Day
Driftwood

Flower

Peony

Lily

Landscape

Green Fools
Bouffon moonrocket.

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