From the Gold Prospectors July/August 2012 issue
By Blue Sheppard
Out in the field, while you're dreaming of the big bonanza, searching for that glint of gold, there just might be another glint. Don't let your gold fever make you blind to those "humbler" finds, called gems.
When I was in my early twenties, I worked at Giant Mines up near Yellowknife, a city in Canada's Northwest Territories. We were all so "geared for gold" — so hot for that yellow metal in the frigid minus 50-degree arctic winters — we worked six days a week. We talked about that yellow glint in every part of the mining process, which begins with the men deep underground.
Raw ores were mined deep below the frozen earth (and deep below Great Slave Lake). Drillers and muckers blasted their quota of gold ores, tramming these out to the dump station grizzlies. From there, these loads were transported by miles of conveyor belts to the banks of cone crushers and hammer mills on the surface some 2,000 feet above.
These rocks were smashed into fine sands. This was the beginning of the milling functions in this long production chain. These "fines" were then roasted in an arsenic refractory-type oven and then further ground down in huge ball-mills, the size of RV motor homes.
These rapidly rotating drum-shaped mills with cannon balls inside them were designed to beat the bejeezuz out of those fine sands. The noise levels were beyond belief — a loud, continuous cacophony.
The ball mills produced super fine mud. These ores, now sludgy materials, were piped into the floatation tanks where surfactant chemicals were added in monster 15,000-gallon tanks with rotating paddles that would constantly stir this slurry while a bubbly foam began to grow into a thick froth on the surface which contained most of the gold values. (Yes, gold floats in this stuff!).
The froth was skimmed off into the C&P (Clarification and Precipitation) unit, where I would strain the water out with huge suction filter panels and then clean those panels carefully ducting these precious solutions into the final stage — the filters.
These filters were plates of metal wound with a special cloth and set into a large press. The solution was then pumped into these filters for up to two weeks, leaving a very black slime in the cloth, which we hoped would become heavy. The waters were tested as they entered the barren tank for S.G. (specific gravity) to see if these waters were carrying any gold. We wanted all the gold to get caught in those filter cloths, so these barren fluids were monitored very intensely by me and the big executive bosses.
Then, one day, the superintendent would give us the order to release the filter press. That was what we did; we shut off the flow, then opened that huge stack of metal plates to finally remove all the cloth from it. The plates were cleaned meticulously. All the yards of sludge-loaded cloth were packed up with extraordinary care and even our white cotton gloves and work smocks (because they had smears of black mud on them) were placed into secure drums and transported by armed vehicle to the smelter building.
I went along in that armored truck to the smelter, a block building with bulletproof glass and an armored door that opened for the truck to unload. Next came the hard work as we added other materials to this lump of cloth including black sludge, borax, soda ash. This mixture was then shoveled into the gas-heated blast furnaces, ceramic retorts that made a sound exactly like a jet engine. There were two furnaces inside this cinder-block buildings. As the noise reached deafening levels, we looked at each other in disbelief that we could survive this bone-rattling roar.
Oh, and one other thing ... the heat! The temperature rose to over 115 degrees in that room. Some of you young'ens complain about your work place environment? Kids, it was 115 degrees above zero inside, and 50 degrees below zero outside, so, take your pick!
We ate our salt tablets and worked until those furnaces were full. Soon, the jets of blue-white flame melted the black sludge into an orange gooey fluid that glowed like a volcano. We then wheeled the "pig" into place. (No, not the owner! He actually was a good guy.) The pig is a heavy, cone-shaped iron vessel that was set under the furnace just right.
Then, the d'or (French word meaning gold or golden) form was placed on top of the pig (See illustrations) and the furnace was slowly rotated to pour out its contents into that d'or form. The heavier molten gold would stay in that "doré pot", while the lighter flux material would separate like oil from water and spill into the "pig" as an overflow. When the dorey was full, we wheeled away the pig and dorey, lifted off the dorey pot and flipped the pig over to flop out that big, cone-shaped slug of glass impurities.
When the dorey was flipped over, and there would be an ingot of 99 percent pure gold weighing about 65 pounds. The work was repeated all day, until we ended up with 20 to 30 of these ingots, or bars, as they were called, all stacked-up on that metal table. What a sight to behold — burning hot fresh gold bars about 9 or 10 inches long — yet, sooooo heavy!
We would hear the siren marking the end of our work day. By then, the shift bus would arrive with the laborers from the deep tunnels and the Royal Canadian Mounted Police, too. The RCMP officers, known as Mounties, ushered troops of miners past the heavily clad bulletproof glass window. One by one, these poor tired drillers and muckers would get a brief look through that metal grill and glass at the fruits of their labor. Some of their faces were smiling with pride, but many would contort into a demon-possessed grimace and some of them would mindlessly claw at the window frame until a Mountie would shove them away. Yes, gold can do that — turn a man into a monster. I saw it happen many times to regular guys in this business. Well, that was an eyeful for a 21 year old kid!
After the armored truck loaded the gold, I would then head back to the bunk house and get a shower, then head off to the pubs in the town of Yellowknife a few miles away. There were a few raunchier bars and pubs in that little town, but one, the Old Stope, had the cheapest beer in the far north and was the wildest. Men of every race, religion, bad habit and nation would meet in this pub and drink until they fell over or got arrested.
Mining was hard work and the lifespan of a miner in those days was listed in Canadian labor statistics as nine years and three months on the job ... and they were proud of that! So, we would party just as hard as we worked in those four-month-long nights of northern winter.
One night, amidst the brawls and hurled insults, a man arrived wearing the standard parka, a "hoodie" made of seal skin and fur. He sat at my table near the back, where I was talking to a few Scotsmen who had recently been signed on at Giant.
After a few beers, he began to tell us that he traded furs, food, medicine, tools and ran a dogsled out to remote, roadless regions, where he was prospecting. He told us that he had come across glitter other than gold.
Some other glitter besides gold? Wasn't gold the only glitter?
The men at my table began to chide him. As they did, he reached into his parka and pulled out a leather pouch, pouring the contents out onto a napkin in front of us.
The men laughed: "These are a bunch of pebbles!"
But, this sledder, prospector and trader kept his cool and asked if any of us knew what these pebbles were. Of course, I opened my big mouth and pointed first to a sweet octahedral gem crystal and said: "Is that what I think it is — a 10 hardness?"
The man shook my hand and introduced himself as Duncan. He told me about the diamonds he had found from 1964 to 1966 because of a first find, a small garnet.
"That garnet led me to scan the area for more. And, that is when I started picking up a diamond or two," he told me.
Duncan was looking for money, enough to grubstake a year of staking claims to a vast area where these stones abounded in abundance. The amount he needed: $3,000!
Yup, remember that next time you say "No!" to a "crazy mining deal" folks. The industry caught-up with Duncan decades later and they scooped his territory, his dream of claiming the richest gem deposits ever found in North American history. And, if I had given him that money and done that grubstake, well ... what might have been?
Those diamond deposits are now valued a wee bit higher than the $3,000 Duncan needed. They are worth billions of dollars. Duncan told me that a humble garnet had led him to his finds, a reddish garnet! And, the rest is history.
Garnet, a type called harzburgite, is one of the associated minerals found with diamonds as they both form deep in the earth in upsurging kimberlitic or lamprophyric pipes. Garnets, similar to what they use in sandpaper, are a signal to you to look for other amazing crystals alongside gold while dredging or panning those alluvials.
I took the ice bus back to the bunk house, crawled into bed, still seeing those diamond and garnet crystals in my head. I awoke the next morning to go back to work at the Giant Mines, not really understanding until decades later how close I had come to one of the greatest gemstone discoveries since the De Beers family found the same thing in South Africa over a century earlier — billions of dollars in diamonds from the sign of a humble garnet!
The name garnet is derived from the latin "granatus", meaning grain. But, many believe it originates as a word from the name Pomme Granatus or Pomegranate, which has seeds with the color of red garnet and these seeds clump together much like garnet in nature.
Yes, the ultramafic igneous rocks more than 100 miles deep below the frozen tundra had spewed diamonds millions of years ago, but those rocks spewed common garnet too, and now the huge corporations and government officials take their applause and their money, while Duncan lived his life in obscurity. Now, you know the true backstory of how it first happened and who it really was that first found the biggest diamond bonanza in North American history.
TYPES OF GARNET
There are six basic types of garnet:
The Pyralspite Series:
Pyrope (Mg3Al2Si3O12): Deep red to pale red. Rhodolite is two parts Pyrope and one part Almandine. Greek meaning "firelike."
Almandine (Fe3Al2Si3O12): Deep red to brownish. Common garnet, but gems can be rich red in color. Possibly from Allemagne, the early Franco name for Germany.
Spessartine (Mn3Al2Si3O12) : Orange to dark red. Spessart is a location in Bavaria. Other varieties include Mandarin.
The Ugrandite Series:
Uvarovite (Ca3Cr2Si3O12): Rich green in very small crystals. Russian Count Uvarov.
Grossular (Ca3Al2Si3O12): Yellow to green to red. Latin name for "gooseberry" color. Other varieties include Hessonites and Tsavorites.
Andradite (Ca3Fe2Si3O12): Yellow to brown to green. Portuguese mineralogist named Andrada, and the variety Demantoid, more rare and valuable and fiery than diamonds.
Blue Sheppard is a mining engineer and master gem cutter based in Southern California. He can be reached at blue@gemsofpala.com.
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