My newest release is Miner in Petticoats. It's a story about a man building a future for his brothers and their families. The story is set in the gold country of NE Oregon. I used a well known creek in the area, Cracker Creek, and had the hero build a stamp mill. There were stamp mills in the area but not on this creek. It was a liberty I took with my story, but I did my ground work on how the mills were set up and how they ran.
A stamp mill is a large device used to crush rock and extract gold and other precious metals from the stone.
There are several ways to mine gold:
The easy method is panning. I had the fortune to try my hand at it when my husband and I cruised to Alaska this past month. We toured a jump-off camp on the Chilkoot trail and they had mining pans for each of us to practice the art of panning.
To pan you need anywhere from a 10 inch to 20 inch pan that's made of metal and has a concave bottom with a 30 to 40 degree angle on the sides. Don't forget a pick and a shovel to dig below the bedrock. For the pan method of gold mining you find a spot on a stream where the water is moving slow as the fast moving water would have tumbled the gold along the bottom of the stream, depositing it where the flow was slower. The gold, being heavy, would work its way down into the bedrock of the stream. Shovel away the top layer and fill the pan with gravel, set it in six inches to a foot of water, and knead the mixture with your hands. This breaks up any chunks of clay and causes the heavier material to move to the bottom of the pan. Toss out the larger rocks and debris. Shake the pan vigorously, making sure the small nuggets or grains sink to the bottom of the pan. With the pan slightly tilted, lift it quickly up and down, letting the lighter material wash out over the sides of the pan. This could take up to ten minutes to get down to a small amount of heavy material in the bottom of the pan. Keep adding small amounts of water until you have the material down to one layer and spread across the pan. You can see the gold and pick up the small pieces with a dry fingertip if they are small. Or pick them out if they are a fair size.
The next method is a sluice box. A sluice box is a wooden or metal trough roughly six feet long with a series of riffles placed in the bottom of it to stop the heavier minerals. There are several variations. One is pictured on the cover of my book Miner in Petticoats. The heroine in my book uses a sluice box to find gold from the trailings she digs in her mine. The sluice is designed to speed up the process of separating gold from the sand and gravel. It is easier and faster than a pan and less expensive than other operations. The riffles are usually pieces of one inch lumber placed at intervals along the bottom of the box with a cloth placed beneath them to capture the smaller particles of gold. The cloth can be removed periodically and washed dipped in a tub, rinsing the debris from the cloth to later be panned. A box can be set up anywhere you have a source of water. But it should be set up at an angle of roughly one inch per foot of slope. This allows the water to run down at a slow enough rate to leave the heavier objects trapped in the riffles.
The Cradle or Rocker is another variation of a sluice process. It is faster and harder to build and work. It is a sluice on rockers. It can be agitated, forcing the gravel and other materials to travel faster, yet leave behind the heavier objects. It takes two men or more to work a rocker.
The next method a miner with a small producing mine might invest in was a stamp mill. Like my hero in Miner in Petticoats. They used gravity to force the rocks through the system. They built the mills on the side of a canyon or hill arranged in descending steps. They also used water to run the stamps and wash away pulverized rock so they also had to be near a dependable water source. Mills could be ordered through catalogues. A simple stamp mill could be built by anyone with building knowledge. At the top of the mill, the rock dug from a mine was dumped into a grizzly or grate. Any rock that didn't fit through the grizzly rolled down into the crusher where it was made smaller. All of this filtered down into the stamp battery. This could be anywhere from three to five (in the smaller mills)or up to 100 large square stones weighing 1000 pounds each on the ends of poles that moved up and down like pistons at alternating intervals that pulverized the rock. This then moved down to amalgamating plates. The amalgamation table was coated with mercury and the gold would adhere to the mercury and the "amalgam" would be removed from the plates and the gold extracted from the mercury. After that process the residue of crushed rock and water would wash across the concentration table to collect anything the amalgamating plates missed. These tables were the size of pool tables with shallow riffles and mounted at a slight tilt.
Mining was not a lazy man's occupation. It took long hours and lots of backbreaking work to glean enough gold to make a decent living and money to back you to start up an enterprise like a stamp mill to make your mine pay off even more.