I’ve written about panning for gold and rockers and Long Toms. Inevitably, as the search for gold during the California Gold Rush, the miners developed more sophisticated methods of extracting gold. Sluicing was the next development after Long Toms.
While some consider Long Toms to be primitive sluices, the difference is one of scale. Sluicing could process much more dirt than the earlier methods of mining.
The sluices of the Gold Rush were usually long wood boxes with “riffles” in them to catch the gold. As with the rockers and Long Toms, the intent was to get water to do most of the work of separating gold from dirt and gravel. The sluice boxes were placed in water at a slight downhill tilt so that water flowed through them, with enough current to wash out sand and gravel, but not enough to wash out the gold.
Whereas Long Toms were around six to twelve feet long, sluices could be hundreds of feet long. The sluice could be a whole series of connected boxes. Because so much effort was involved in building the sluices, the boxes were typically built on the mining claim frrom whatever wood was available.
Moreover, sometimes a whole stream was dammed and diverted to expose the riverbed, and the rich dirt that had been under water was shoveled into the sluices to extract the gold.
Obviously, even though sluicing was a labor-saving method of mining, it still took a lot of manual labor. After building the sluices, men had to shovel dirt into the sluice box. The men needed to shovel fast enough to process a lot of gravel, but not so fast that the riffles were overloaded. If the dirt ran over the tops of the riffles, then the riffles could not function to sort the dirt and catch the gold.
Once the heavier pieces had been caught in the riffles, they had to remove the larger rocks by hand. Leaving the larger rocks would let the current scour sand and silt (and maybe gold flakes) from around the rock. Particularly at the lower end of the sluice box, the gold might escape altogether.
In addition, the miners had to move the tailings from the end of the sluice box, so the water wouldn’t back up into the sluice.
Finally, and most importantly, the miners had to pan the remaining silt for gold flakes and nuggets. That’s the only way to make the sluicing productive—find and retain the gold that was trapped by the riffles.
It could take shoveling several hundred pounds of gravel to get a few ounces of gold. But these large sluices could process hundreds of cubic feet of dirt per day—far more than several men could pan by hand.
As the number of miners in California grew through 1849 and into the 1850s, individual miners were replaced by corporate operations. More complicated machinery using hydraulics and heavy earth-moving equipment became more common. Whole hillsides and mountains were moved, and ravines scored in the increasingly difficult search for gold. Increasingly, water was moved to the dirt in long aquaducts, rather than moving the dirt to the water.
More and more, only capitalists with money to invest could make a profit from mining.
What impresses you the most about the increasing mechanization during the Gold Rush?