Finer than sand
The miners only got to a small portion of the gold at Blue Point. They spent years washing away the upper layers of gravel before getting to the richer, gold-bearing material that lay in the lower portions of the ancient river channel, close to basaltic bedrock. They were just getting to the richest gravels when the Sawyer decision abruptly shut down hydraulic mining in 1884. And though the miners knew they’d only extracted a small portion of the gold that lay in that valley, once hydraulic mining ceased there was simply no cost-effective way to get to it.
The gold was finer than sand, having been eroded from the upper Sierra by the ancient Yuba River, and was bound up in cemented river gravels so hard they had to be dynamited before they could be washed into tunnels by the hydraulic cannons. For every ounce of gold recovered, the miners had to blast away, on the average, more than ten tons of material. Given the vast quantities of gold-bearing gravel that lay in the valley, hydraulic mining at Blue Point was certainly a very profitable endeavor, but once the miners could no longer flush thousands of tons of waste rock per day through the tunnels and into the Yuba River there was no way they could process the quantities required for profitable mining. And so most of the gold still remains intact, cemented in the ancient river gravels beneath the valley floor.
Though for the last hundred years or so a series of operators have tried to figure out how to get at Blue Point’s gold, most have gone bankrupt (and, according to legend, a few insane) in the process. Although the Tarr Mine, with its ambitious aerial tram and stationary dredge, was by far the most grandiose, many others have attempted to “drift mine,” digging shafts down to gravels that might be rich enough to be worked profitably by a small operation. And more recent operators have tried to quarry the site, selling cobble along with the extraction of gold, but they went bankrupt as quickly as their predecessors. And now only the gold remains.
But are things different, now that the price of gold exceeds $1000/oz., the highest price in history? And now that newer, improved technologies are available which can more effectively extract the stubborn gold from the gravel in which it’s bound? Might now be a good time to consider a modest, surgical, even ‘green’ operation, tunneling down to the high-value gravels in the ancient river channel, extracting perhaps ten or twenty tons, not thousands of tons, per day, and leaving the surface, with its wetlands and wildlife and historic resources, undisturbed? And might the resources of such an operation be a means to keep the Blue Point property intact and preserved, and not otherwise developed or subdivided, until such time as a non-profit organization or public agency might be able to acquire and conserve it?
Though a lot of questions remain to be answered, one thing is certain – the call of the gold beneath the Blue Point bowl is as clear and as compelling as ever.