Black Hills Pioneer (Spearfish, S.D.)
October 28, 2005


By Donna Smith

DEADWOOD -- They already know the soil and the water are contaminated
and some cleanup has already been done, but now the Environmental
Protection Agency begins the process of assessing the risks to human
health posed by the arsenic, lead, mercury and other heavy metal
contaminants left behind at the Gilt Edge Mine site near Lead.

On Wednesday evening, more than 20 citizens gathered in the Galena
Room of the Hampton Inn in Deadwood to hear EPA toxicologist Susan
Griffin explain the human health risk assessment the EPA will complete
at the Gilt Edge site, which is about five miles east of Lead.
Griffin began her informal presentation by providing some background
information on the mine. She said the mine operated from 1876 to 1998.
More than 120 years of mining left scars on the land and contamination
in the water and soil. When it was clear that the owners of the
property were not going to clean up the site, the government stepped

In February 2000, then South Dakota Governor Bill Janklow requested
that EPA Region 8 propose the site for the Superfund National
Priorities List (NPL) and provide emergency response, as well as long-
term remedial cleanup at Gilt Edge. The site was proposed for the
Superfund NPL in May 2000, and final placement of the site on the NPL
was announced in the Federal Register in December 2000.

In the months and years since that designation was announced, the EPA
has held a number of public information meetings to outline the
process the EPA follows when cleaning up a site like Gilt Edge.
Gilt Edge is located at the headwaters of cold-water fisheries and
municipal water supplies of the northern Black Hills. It was a 258-
acre open pit, cyanide heap-leach gold mine, developed in highly
sulfidic ore bodies. The operator (Brohm Mining Company of Canada)
became insolvent, leaving 150 million gallons of acidic, heavy-metal-
laden water in three open pits, as well as millions of cubic yards of
acid-generating waste rock that need cleanup and long-term treatment.

The EPA has already done a significant amount of work at the Gilt Edge
site. "The 70-acre Ruby Gulch Waste Rock Repository is 95 percent
completed. A new water treatment plant has been built (lime/high-
density-sludge process) to more cost-effectively treat the ongoing
acid-rock drainage (ARD) that will result from rainfall and snow until
remaining portions of the site are remediated, further reducing ARD
treatment requirements," according to EPA records.

As the EPA continues its work, the agency also assesses possible
future uses for the site and any potential health risks posed for
future visitors, recreational guests or residents.
Citizen Dan Leikvold, who is also superintendent of the Lead-Deadwood
Schools, asked Griffin on Wednesday what sort of timeline the EPA has
for completing the human health risk assessment. Griffin responded
that in four-to-six months the EPA will have a baseline risk

The EPA tests contamination levels in surface water and soil at Gilt
Edge. Then the agency's toxicologists develop a "site conceptual
model" or graphic illustration of where the contamination originates,
how it moves through the environment and how humans come into contact
with the contaminants, Griffin said. Human exposure can occur through
the air by inhalation of the dust, by ingestion of soil, sediment,
surface water, groundwater, fish and produce, or through dermal or
skin exposure to contaminants.

Testing by either direct (blood and urine) sampling or indirect means
(using equations to estimate site-specific exposure) then helps the
EPA compare the likely levels of contaminants exposure at Gilt Edge to
known medical benchmarks for toxic levels of the various contaminants.
Griffin used the known adverse health effects of arsenic as an
example. Arsenic is a human carcinogen, meaning overexposure to the
toxic chemical is associated with increased incidents of lung, skin,
liver and bladder cancer. Other non-cancerous effects are also listed.
Because the scientists know at what concentrations the adverse effects
of arsenic occur, they can then compare those known levels to the
exposure levels calculated at the Gilt Edge Mine site to estimate the

Testing for the arsenic levels can be expensive, and Griffin said the
human testing is up to the county or state health officials. The
county and state can get financial support for such testing, and that
is an area the EPA can help explore for the Gilt Edge project.
Citizens also raised questions about the possibility that contaminated
water could leak far beyond EPA sample testing sites. Griffin said
that the agency welcomes ideas from citizens about the right places
and ways to test for contamination.

The EPA might also consider formation of a group to meet regularly to
discuss issues at the Gilt Edge site. Griffin said the agency values
public input on the process, and she asked if those present would have
any interest in such a group.

EPA representatives may return to the Northern Hills one more time
before the end of the year, but that will be announced in plenty of
time to allow more public input, Griffin said.

Exploration of potential future uses for the cleaned up land
continues, and citizen input is welcome throughout the process.

Copyright The Black Hills Pioneer 2005