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Canyon Gold Dredging at Crow Creek - 4/24/99

Steve Herschbach

The summer of 1998 was one of the best summers I've seen in Southcentral Alaska for gold dredging. The spring thaw was exceptionally early, and the fall freeze very late. Gold dredging in Southcentral Alaska is best done early and late. The water is very low in the spring and fall, but high most of the summer as the snow in the high country melts. Spring, when the creeks open, but the higher elevations are still frozen, is my favorite time. The daylight is long, and the temperatures are warming. The only problem can be getting equipment in when the snow is still deep on the ground. Fall, when the higher elevations freeze up, but the water is still flowing, is also very good, and I have usually done better this time of year. The daylight is getting shorter, and the temperatures are plummeting, but the timeframe is usually longer than in the spring. It is however just plain colder this time of year.

Spring dredging in Southcentral Alaska can start as early as March, but more often April. The water usually starts to come up in early June, and so the canyons and gorges that are most productive become difficult, if not impossible to work. The water levels begin to decline at the end of September, and dredging can usually proceed into November. A few tough individuals may work in the December to February timeframe, but these kind of operations are extremely difficult and rarely undertaken, unless the weather is unusually mild.

In 1998 I was able to start dredging at Crow Creek Mine in March, and was hoping to repeat the early start this year. Unfortunately, record snow in the area kept the creek frozen until much later this year. If a person is determined to start mining anyway, it is possible. A friend, Andy, went down to Crow Creek in March. He shoveled all the snow off a stretch of creek, then chain sawed out sections of ice to open up the creek. Needless to say this is very hard, time-consuming work, but Andy's job allowed him the time to pursue this task. I decided to wait for the creek to thaw out on it's own before I started. Andy's reward for his hard work and earlier start has been about a pound of nice, coarse gold so far. The pictures below are of Andy, his pound of gold, and his suction dredge in lower Crow Creek canyon.

andys-gold-dredge-crow-creek.jpg  andy-showing-crow-creeek-gold.jpg
Andy with his gold, and his dredge on Crow Creek

I went down to Crow Creek Saturday morning, April 24th, with the intention of digging out my equipment and getting it setup on the creek. I had heard from Andy that the creek was starting to open up finally. There was still 3-4 feet of snow at the parking area, when at this time last year there was no snow at all! I talked to Andy, and took the pictures above. He is wrapping up his operations at Crow Creek soon, and is looking forward to some mining at Nome and on the Fortymile River this summer.

Crow Creek Mine has two basic areas: the lower canyon, which was mined first, and generally mined out completely to bedrock by the old miners, though some side areas remain. This area is a steep, rock-walled gorge. The upper portion of the mine opens up into a wider area that is still above bedrock. This was the site of later mining, and the tailings from the large scale hydraulic mining in the upper area were flushed into the previously mined canyon below. I have been working the canyon deposits for years. The material in the canyon is tailings that have been reworked by floods over the years, reconcentrating the gold that was lost by the inefficient hydraulic operations of yesteryear. The gold is generally smaller, but very consistent. Sometimes larger gold is found, as is the case with Andy's gold above. It is most likely gold lost from material flushed from a side canyon into the area he was dredging, and so has some coarser gold than is usual for the canyon.

The canyon portion of Crow Creek is closed to the general public, and only available by special permission of the mine's owners. The terrain is very rough, and the canyon is generally only minable in the very early spring and late fall. During the summer, the glaciers that feed Crow Creek melt, and it swells in size to where it is difficult, if not impossible to cross. It fills the canyon with wall-to-wall water. The creek also fills with glacial silt for the entire summer, so underwater work is difficult due to the water being so muddy. The clear water seen in these pictures is not the norm for Crow Creek in the summer, but will only be seen when freezing temperatures keep the glacial melt from flowing.

I grabbed my pack and shovel and proceeded to where I had stored my dredge the previous fall. I have worked at Crow Creek for many years, and Sean Toohey is kind enough to let me store my equipment at the mine. This can be a risky proposition in some areas, but Sean lives at the mine year-round, and so he keeps an eye on the equipment for me. I was dismayed to find my dredge buried under 8 feet of snow! Needless to say it took the entire day for me to dig the largest hole in the snow I have ever dug in my life. The sheer weight of the snow caused one of the Marlex floats to be partially deformed, but it was not cracked. A cross brace on the bottom of the sluice box was flattened, which I hammered back out. I also managed to put a hole in one foot valve while chipping it out of an ice layer at the bottom of the hole. All in all, though, I was lucky the extreme snow depth (over 25 feet fell at the mine this winter) did no more damage than it did. I have learned from past years to be careful to arrange items in such a way as to not be crushed by snow loads.

Steve's Dredge Site on Crow Creek

The pictures above show the area I am going to work, both as I found it, and after I opened it up by hacking away at the snow with my shovel. This is where I stopped dredging last fall, and below Andy's dredge. His site is just around the farthest corner visible upstream in the second picture above. I got my dredge mostly assembled and in the water by the end of the day Saturday. Note that the water is murky in the second picture as compared to the first. This is from snow melt and small avalanches upstream as the temperatures warm throughout the day. Because of this, and the possibility of other dredging upstream of me, I try to start as early in the morning as possible. Luckily the days are getting longer, and it is easily light enough to mine by 6AM. After taking a careful inventory of additional items I would need Sunday, I headed back home.

Sunday was clear and sunny, and the conditions for dredging were perfect when I got back to my dredge. I replaced my broken footvalve, attached the remaining hoses, and overcame a startup problem with one motor. Water in the fuel bowl, a common thing when running motors around water all day, had to be drained. Then it was time to dredge.

The canyon walls have pinched in on me at this site, and the gold is deposited near the surface in a layer of reconcentrated tailings. I am following the remnants of the old sluicing system, which was supported by uprights and cross-pieces of hemlock logs. The sluice is gone, but remains of the support framework are buried in the creek. Keep in mind that this area was mined completely to bedrock, which at this spot is 4-5 feet below my dredge. The old sluice was built in the bottom of the channel, and has since been buried by the tailings from mining upstream. The top layers, anywhere from 1-3 feet in thickness, are concentrated tailings, and quite rich with gold. Below that is a jumble of broken rock, wood, and other debris discarded into the channel behind the old miners as they worked up the channel. I have dredged the bedrock in the past, and found small amounts of gold the old-timers missed, but found the overall effect was less gold per day in my dredge, as I had to work too much worthless material to get there. So now my goal is to mine down until I reach a layer of sand that lies on top of the debris layer.

Since the channel has narrowed at this spot, the creek has scoured the top pay layer and it is thinner than normal. I hit the framework for the old sluice system less than a foot down, and the pay layer is only a couple feet thick. I saw quite a bit of gold as I worked, so it looked ok, but not as rich as the area I had worked below, where the channel flares out wider. I expect the gold to improve as I work forward, to an area where the channel once again widens out.

The pictures below show my dredge, and a shot of the work area with the old sluice support framework visible as submerged logs running up the creek. My dredge is a Keene 6" model with the nozzle reduced to a 4" opening. This helps prevents clogs, and allows the unit to qualify for the EPA small dredge permit. This permit is required to dredge in Alaska, and is divided into two basic permits. The small dredge permit is for dredges with a 4" or smaller nozzle opening. The hose may be up to two inches larger than the nozzle opening. The small dredge permit has a basic set of requirements, and requires no reports to be filed with the EPA. Anything with a larger than 4" nozzle opening requires a stricter permit that has daily logbook requirements, with a report to be filed at the end of the season. 2012 Update - these permits have since been revised to allow dredges with up to 6" nozzle openings to operate without reporting, and are now issued by the State of Alaska Department of Environmental Conservation (DEC) instead of the EPA.

Steve's Gold Dredge

The dredge is powered by twin 5.5HP Honda pumps, and has an air compressor to supply me with air if I need to work deeper material. I use a Harvey's drysuit and generally mine with a mask and snorkel, unless the material to be worked is more than three feet down. I then go to the hookah air supply system. This dredge has been a very dependable unit, and has served me well. It can be broken down to pack in, and takes me about fourteen round-trips by myself to pack to a particular location. I find it very easy to operate the unit by myself. Working with a second person does not double the production, so if a 50/50 split is made, I end up with less gold. For this reason, I work the unit by myself, and if I partner up with someone, they have to use their own dredge.

I have a plastic tray mounted on the frame ahead of the engines to hold tools and items such as my gloves when I take them off. All the hoses have quick release couplers, and the pumps have been tapped with drains to prevent them from freezing up in cold weather. Hoses have been attached to the oil drain plugs on the motors, so easy oil changes can be made without removing the pumps from the dredge. Everything is setup to keep my efforts to a minimum. This allows me to get six to seven hours of actual dredging time on the nozzle each day. A single six gallon jug of gas is packed in each day to supply the motors.

The results? I dredged about 5 hours Sunday and ended up with 1.4 troy ounces of gold. Basically an average take, but better considering the rather short work time. I usually average 1-2 ounces of gold per day at this location. I'll try and get in longer days next weekend now that I am set up, and see what develops. The gold itself, also as usual, is on the smaller side, since it is primarily gold lost by the old mining operation.

1.4 ounces of gold from Crow Creek Mine
1.4 ounces of gold from Crow Creek Mine

~ Steve Herschbach
Copyright © 1999 Herschbach Enterprises

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