Question to Steve Herschbach

[Silicon John]

Steve, It goes without saying that I am pleased for you. The large gold deposit find at your Moore Creek mine is impressive. Also I want to again thank you for the time you mailed me the disk with the photos of five trips that you made to the site of the Chisana Gold Rush. As you remember my father, Roy Byram, was in the 1914 gold rush and then later hauled supplies to that mountain top. He took a lot of photos and as he was paid in gold, was able to bring gold back to Nebraska from his years in Alaska

What this post is all about is to ask if you could fill us in on how a gold deposit, such as has been found at Moore Creek, will be mined.

It seems that a rather large mill would have to be constructed. After the ore is mined (big equipment), there is the grinding and gold separation. At the Homestake mill in Deadwood, SD they grind the rock to flour fineness and then separate the gold out with sodium cyanide. Then they have to use bacteria to get the cyanide out of the water before the water is released. Perhaps they will use heap leaching but still there must be a cleanup.

I have been to Ganes Creek two times for a total of three weeks. Doug Clark said in 2006 that it cost $1.00 a pound to haul equipment in and that was by bringing it up the Kuskokwim River by barge and then over rough roads to Ganes Creek. That is why that complete 1920 era machine shop was still sitting there and was not salvaged. Moore Creek is a little farther off the beaten path than Ganes Creek. Doug had some things flown in. Two years ago diesel was over $4.00 a gal delivered and aviation gas was like $6.00 at McGrath. I know that gold is up in price but the cost of transporting the amount of equipment and energy needed to mine such a deposit just boggles the mind. What can you tell us? Can the ore be hauled to a mill at less expense? Do they have such a thing as a portable mill? Where will the workers live? Would it not just be simpler to pay off the national debt?

 

[steve herschbach]

Hi John,

Well, we don't have a hardrock mine yet, but I'm far more hopeful now that we will. The good news is that our ore is free milling, so in theory all you need to do is crush it and run it over a concentrating table, and then refine it. Leaching is optional depending on additional values that could be recovered.

The cost of mining in remote Alaska is indeed high. Donlin Mine is being developed about 90 miles from us and it is a super high cost mine as they have to bake their ore due to sulphides. So their biggest obstacle is in where to get the energy to run the furnaces. We do not have that problem, thankfully.

The bottom line is since costs are high a gold deposit that might be mineable in Nevada will not become a mine in Alaska. We need big deposits. For Moore Creek to be feasible as a large mine will mean we need to prove up around 2 million ounces of gold with the drilling program. More is better. That will justify building a large airstrip and bringing everything in by Herc. Barge costs have gotten so high these days it is really not that much more to fly stuff in. And in our case a road would have to be built 30 miles to Ganes Creek to get road access to to barge supplied equipment.

In theory if they only find 100,000 oz of fairly high grade ore I can mine it myself. Just need a good little ball mill and a good concentrating table and a blasting license. Just the showing we have so far has a lot of 1/4 oz per ton material at the surface that is so decomposed it can be excavated without blasting. Just scoop it up, crush it fine, and table it. In my case I'd ship concentrates out to be refined.

To give you an idea of what it takes to get a big mine going, take a look at the EPA report on the recently opened Pogo Mine here in Alaska at the EPA website. Pogo took over three years and about 390 million dollars to develop (the report estimated 250 million so pretty good cost overrun!). So they burned up over 450,000 oz of future gold production just to build the mine. But they have around 5.5 million oz in place so they are doing fine.

Steve Herschbach

 

[Silicon John]

Steve

I did printout and read the 21 page Pogo Mine Project Report. Wow! You would need to be a Philadelphia Lawyer with a staff of a thousand to make all the environment studies and to obtain all the permits.

Got to calculating about Moore Creek. If I have the facts right then you will need on the order of 2,153 Olympic size swimming pools of ore (at 3 grams of gold / ton) to obtain 2 million troy oz of gold.

Here is how I calculated: water weighs 64 lb/ cubic foot or 64 x 27 = 1,728 lb per cubic yard. Now if your gold ore has a specific gravity of say 3.5 ( another estimate which I only looked at quartz and other minerals and took a guess) that would give your ore 6,000 lb / cubic yard. That is 3 tons per yard. So at 3 grams / ton (you said your ore was from 2.17 g/t to 8.86 g/t) it would take 32/3 = 10.7 tons per troy oz of gold. And 10.7 / 3 = 3.56 or say 3.5 cubic yards for each troy oz of gold. Note: g/t is in grams per English tons isn't it?

An Olympic size (50m X 25m x 8 lanes was given to have 2,500 cubic meters volume. Convert that to cubic yards as I think in English gives 3,250 cubic yards.
And 3,250 / 3.5 = 929 troy oz per swimming pool. Thus 2,000,000 oz of gold would take 2,000,000 / 929 = 2,153 swimming pools to get 2 million oz.

If my units and calculations are correct I still don't know how big an ore body needs to be as I can't think in Olympic Swimming Pool units. Anyway you have a great and interesting project and we all wish you the best of luck when the drilling and mapping starts. Please keep us posted. We can live it vicariously.