MCLAUGHLIN MINE, Calif. - Homestake Mining Co." s Ray Krauss ambles along the banks of a lake his firm built to supply water to its McLaughlin Mine in Northern California. He talks glowingly about his 17 years as manager of environmental affairs.
First he got permits for the cyanide-process
gold mine just 70 miles north of San Francisco. Then he saw the
mining through without serious incident, and even received
accolades from the Sierra Club, the Soil Conservation Society, and
Oregon's High Desert Museum.
He did more than
simply avoid disasters. Krauss says the mine improved the land
around it. The mining company has cleaned up three abandoned
mercury mines, removed cows from most of the 11,000-acre site, and
collected two decades of baseline scientific
But most significant are the company's
efforts at reclamation: Native oaks now grow atop waste-rock dumps
and the mine has kept its heavy metals from worming their way into
the downstream food
"McLaughlin is an
environmental showcase," says Mike Steeves, Homestake's director of
investor relations. "It's the one we tend to show off."
"It's interesting how 200
acres of mine pit can support 10,000 acres of (nature preserve),"
boasts Krauss. The numbers might be a stretch - counting the
processing facilities, the ratio is more like 10 to 1 - but the
principle is thought-provoking. Homestake has channeled about one
of every 40 operating dollars into environmental efforts, amounting
to some $2 million a year when ore was still being extracted and
waste rock piled for burial.
no one was clamoring to plug the hundred-year-old mercury mine
tunnel that was channeling acid drainage into Davis Creek, or to
remove the processing waste from 19th century mercury retorts,
which have discharged heavy metals into local streams. Homestake
found it easier to clean up the previous miners' mess than to argue
about whether the mercury was coming from the old workings or from
its new mine.
It is this enlightened approach
that has earned Homestake the respect of figures such as University
of Nevada Professor of Environmental and Resource Sciences Glenn
Miller and of organizations including the Mineral Policy Center.
"They're at the top of the heap right now in terms of major mining
companies," Miller says, "but that still isn't saying a whole lot."
And when the Mineral Policy Center prepared "report cards' on
various mining firms in 1992, says senior research associate Carlos
Da Rosa, Homestake walked away with the most positive one. The
Mineral Policy Center's recent book, Golden Dreams, Poisoned
Streams, says the McLaughlin Mine "demonstrates that hardrock mines
can be both profitable and environmentally responsible."
Scientists also give the McLaughlin Mine high
marks. For more than a decade, Professor Peter Connors of the
University of California Bodega Bay Marine Laboratory has studied
the California roach in the streams that drain the waste rock
sites. He doesn't hold the mine responsible for any heavy metal
concentrations in the fish. "Natural conditions and variations
explain the variation in their populations," he
The California Native Plant Society's Joe
Callizo has been tracking rare plants such as the serpentine
sunflower and adobe lily near the mine and has seen "very little
encroachment" from Homestake's activities. "When we've seen the
occasional tire track or fallen fence, we've reported it, and
Homestake has fixed it immediately," Callizo says. Indeed, most of
Homestake's 10,000 acres seem more like a gently used ranch than a
mine, covered in a mosaic of woodland, rolling grassland and
Given the mine's location just 20
miles from the Napa Valley wine country, it's not surprising that
Homestake chose to make this its premier effort at land stewardship
when it sought approval for the mine in the early 1980s.
"California is a more
populated area," says Da Rosa. "There's a greater degree of
environmental sensibility, so they had to respond to that."
Frances Burke had moved to nearby Rumsey just a
few years before, having come from more urbanized Santa Cruz "for
peace and quiet," she recalls. Add to that the fact that her
orchard's irrigation water comes from Cache Creek, downstream of
Homestake's main reservoir, and she felt she had to make a stand.
But "when we realized we couldn't make them go away, we worked hard
to make the regulations as strict as possible."
Neighbors like Burke kept close tabs as the mining company sought
the 327 permits it needed to operate. Homestake engineers designed
a system for ore and water to be mixed in a slurry which is piped
four and a half miles away from the mine site, to a location where
tailings would present less of a threat. Homestake also chose to
process the ore in tanks, rather than by piling it into huge heaps
and doing the leaching on the ground. Waste rock dumps were
designed with settling ponds to contain surface runoff and with
clay caps to surround deposits of acid-bearing rock. The dirt roads
were to be watered to keep down the dust raised by moving 100
million tons of rock over the lifetime of the
Even so, there have been surprises, one of
which demonstrates the adage that it is possible to drown in a pool
whose average depth is one inch.
chemists analyzed the waste rock and concluded that a mere 7
percent of it had more acid-generating potential than the
alkalinity of the rock itself could neutralize. But the rock
behaved differently in nature than in the laboratory, fracturing
along quartz planes, and exposing fresh pyrites which oxidized to
quickly release sulfuric acid, Homestake environmental engineer
Dean Enderlin said. This pulse of acidity is long gone downstream
before the rest of the rock releases its buffering minerals.
Thanks to this phenomenon, the amount of rock
needing to be contained more than quintupled, says Krauss, from 7
percent to 40 percent. Homestake adapted by isolating the
geochemically active rock in thick clay liners capped with 15 feet
of clay and five feet of soil.
Homestake has traveled a relatively smooth road. Senior engineer
Bill Marshall, a 13-year veteran of the Central Valley Regional
Water Quality Control Board, characterizes the mine's environmental
record as "pretty good," marred only by occasional violations of
heavy metals limits downstream of the waste rock sites. Most of
these occurred when the sediment ponds were overwhelmed by runoff.
Now, a mine pump diverts the water away from the stream.
With all the ore mined and the refining
facilities set to close in a few years, some ambiguities in the
enterprise are coming into sharper focus. Even state-of-the-art
mines leave a trail of risk that will last well into geologic time.
Observers worry that the clay waste-rock
containment will eventually fail, or that the supposedly
impermeable tailings pond will leak. For these reasons, the
University of California would decline any offers to own the site
outright, says Elizabeth Riddle, acting director of the
university's Natural Reserve System. With a lease or license to
conduct research on the site, however, Riddle says the university
would be eager to expand its research base there beyond the 300
acres it already manages.
Though the McLaughlin
Mine has had its lapses, it shows what a mining company can do. And
that puts Homestake and the industry in a somewhat awkward
position. Homestake spokesman Steeves is reluctant to compare
McLaughlin with the heap-leach operation his company plans to open
this year in Ruby Hill, Nev. The environmental protections that
Homestake builds into its mines depend on a host of site-specific
conditions, he hedges. But he concedes that state-of-the-art mining
evolves in conjunction with the demands of the local
"Nevada is a mining
state, where gold mining generates significant employment and tax
base," he says. "If you're in a desert, and not a person lives
within a hundred miles of the site, the permit process will be
writes from northwestern California.