A mass of rock containing ore is called the ore body. Rock without ore is called barren.
Each summer for several years, twenty or so students and faculty of the Nature and Culture Program at the University of California, Davis spent a week in tents under a crescent of black locust trees surrounding a desiccated meadow. The reserve manager would mow the star thistle and rake up the dried cow patties before we arrived, leveling the bleached stems spiking up from gravel-hard dirt clods. We would rearrange the picnic tables into a circle under the low-hanging pinnate branches of an ancient walnut tree. That was our classroom.
In the 1980's, Homestake Mining of Black Hills fame purchased forty thousand acres sprawling across rural corners of California's Napa and Lake Counties. Two decades later, millions of tons of earth had been pulled out of an open pit. Circular, diamond-tipped bits drilled two hundred twenty-five foot boles every day for years. The cores pulled from the boles were fire-assayed. If an array of cores showed gold ore, the boles they had come from were filled with explosives. The resulting rubble rendered precious metal. All the cores are stored in horizontal ranks of cardboard drawers in a low building called the core shed.
Only the first twenty thousand acres had been assayed when the price of gold dropped below what it cost Homestake to mine it. But years of data had been collected in the process of monitoring air and water quality and the health of indicator species, and that data had research value, as did the land. While the processing plant pounded away at extracting gold and silver from the last hundreds of thousands of tons of ore, Homestake began the process of turning [End Page 315] over part and parcel to the University of California Natural Reserve System, a network of acreages, large and small, available for field research and interdisciplinary encounters like ours.
The McLaughlin Gold Mine, named for UC Berkeley geologist Donald McLaughlin, became in its turn the Sylvia McLaughlin Ecological Reserve, named for his wife. An equipment warehouse became a field station. A primitive kitchen was installed at one end of the core shed, in the half-open lean-to where table saws had sliced rock samples. A four-hundred-and-fifty gallon trailer tank was plumbed to a metal utility sink. For our one-week intensive, the rock dust was power-washed away and a local caterer would set up her makeshift kitchen: hot breakfast in the cool September dawn light, sack lunches made and stored in coolers, student-group-assisted dinners.
We have with us, though not all at the same time, university and mine geologists, a fish biologist, several plant biologists, literature professors specializing in everything from ancient Near Eastern languages to landscape design, local poets. My contribution is alchemical.
In the scientific thinking of the 16th century, alchemy has its own logic. All substances were thought to be corrupted versions of a perfect essence, called quintessence, fifth and most essential, beyond and above the four elements. The more desirable metals were thought to be closer to this perfect state: all things longed for it. Lead and copper were more base, needed to be purged of more corruption than silver or gold. In the heat of the alembic, the corruption fled.
The geologist explains that the subduction of the Pacific under the North American plate results in the liquefaction of the rock as it's pushed near the hot magma below. Metals rise and cool in order of their weight: gold first, silver above, and mercury uppermost. In this model, the base metals are the lighter ones; the more precious are heavier and lie the deepest.
For our mid-week shower, we drive to the mine workers' washroom, located in low buildings perched on the edge of the excavations. The floor is slick with wet dust, stone-smelling. Before we enter the showers, [End Page 316] we peer through a cyclone fence to look down into the pit. Wind scribbles across the metallic surface of standing water far below.
Between the excavation and...