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Leadville’s Mine Dumps: Monument or Menance?

Article by Sharon Chickering

Mining – April 1998 – Colorado Central Magazine

An oversized golf course. A tiered wedding cake. Just plain overkill.

Those are some assessments of the reconstructed mine waste piles in Leadville’s Stray Horse Gulch.

AFTER MORE THAN FOURTEEN YEARS of study, investigation, and analysis by the U.S. Environmental Protection Agency, huge dump trucks and other heavy equipment rumbled over the east side of Leadville and up East 5th Street last summer. Work had finally begun on designated portions of the approximately 16.5 square miles of the California Gulch Superfund site.

But the community’s struggle to maintain its historic mining sites has definitely had an impact on the EPA’s work.

Aside from California Gulch itself, Stray Horse Gulch (E. 5th St.) was one of the areas most altered by a century of mining. Until last summer, yellowish, eroded spoil piles lined the road. Acidic run-off, the result of iron pyrite in the soil coming into contact with running water and oxygen, made it next to impossible for even sagebrush or lodgepole pines, both hardy natives, to establish new footholds along the street.

Thus, much of the thrust of the EPA’s remediation concerns surface water. But in keeping with historic preservation, the EPA is also trying to save some of Leadville’s mining backdrop — a visible legacy of the region’s past that still supplies much of the community’s unique character.

Leadville is synonymous with mining, and early residents gave little thought to anything other than locating and exploiting ore. Environmental concerns were not a factor in the nineteenth century, so homes were, and still are, intermingled with mining properties. With an estimated two thousand mines, one hundred fifteen mills and seventeen smelters in such a concentrated area, this is “not an ordinary Superfund site.”

During last summer’s work, mine waste was removed from several sites near downtown and consolidated into recreated mine dumps associated with the Wolftone, Maid of Erin, and Mahala mines — places deemed worthy of historic preservation. But because the volume of excavated material was much larger than anticipated, the resulting piles are out of proportion with their original counterparts.

A geomembrane (plastic PVC liner) and geotextile cushioning (synthetic, nylon-like woven material to provide strength against puncturing) were spread over the tops of the piles to prevent water from leaching through the pyritic spoils. In addition, a layer of dolomitic limestone acquired locally will help neutralize any water that does manage to seep through.

The slopes of these waste piles are unusually steep with angles of 1½ to 1 (horizontal to vertical) rather than the more common 3 to 1, since that better approximates the original piles. Compacted multi-colored rock will provide a covering and prevent erosion of the mine dumps while allowing foot (but not vehicular) access. At this site, no revegetation will be done, however, because as Mike Holmes, EPA Project Manager, explained: “Locals don’t want it to look like a wheat field.”

IN ADDITION, wooden cribbing has been rebuilt to approximate the original at the Maid of Erin.

Adjacent to the Maid of Erin is an area of tailings (mill waste) left from the John P. Hamm Milling & Mining Company, as well as waste materials relocated from the nearby Penrose Mine and Dump and three other smaller mines.

During the 1930s and 40s, the Hamm’s Mill treated abandoned mine dumps to recover gold, zinc, lead, and copper. The area has now been graded and terraced, and a minimum of two feet of clean soil has been compacted on top.

The Penrose, a prominent mine in the Down Town Mining District, was excavated to original ground and covered with soil from a nearby borrow pit. It was scheduled to be revegetated last fall with a hydro mulch of native dry land grass, wild flower and sage seed; mulch; Biosol (an organic nitrogen amendment based on a penicillin derivative) and water.

This is now one of the “newest sledding hills in town” — just steep enough to give a short but brisk ride.

All projects are being designed to contain a one hundred year flood, as well as to remain intact during a five hundred year event. As remediation projects are completed, they will be monitored through at least one spring run-off to evaluate their effectiveness.

Next summer, work is scheduled for upper Stray Horse Gulch, from just above Finntown and the Robert Emmet Mine to Adelaide Park.

Water from Adelaide Park is already of drinking quality with a pH of 6.5. To avoid contaminating it and to reduce drainage through lower Stray Horse Gulch by about 50%, an open ditch or culvert will be constructed to divert the water flow to Graham Park to the southwest.

Partially due to opposition by public officials concerned with historic preservation, the Pyrenees, RAM, and Greenback waste piles will be left intact. Ditches will divert water around the piles, while retention basins collect any seepage. Water in the basins will evaporate and/or seep into the ground to theoretically be intercepted by the Leadville Mine Drainage Tunnel (which was built in the late 1800s to de-water mines in the area), and from there it will go to its water treatment plant.

Wells will be monitored to ascertain whether contaminated ground water actually does flow into the drainage tunnel and not elsewhere. And any sediment collected in the basins will be removed periodically.

In the latter part of the nineteenth century, with more than 100 mills operating, their waste slurry ran down California Gulch into the Arkansas River.

According to Holmes, vegetation still will not grow on some 130 areas of fluvial tailings deposited along eleven miles of the river, from its confluence with California Gulch at Malta to Balltown (the turnoff to Route 82 over Independence Pass). Although responsibility has not yet been assigned, plans call for excavation of some of the most acidic tailings materials, while soil in less acidic areas will be amended and revegetated.

The EPA will also address preservation and stabilization of historic structures this summer. Since the National Historic Preservation Act stipulates that remedial environmental work is not to impinge on historic or cultural resources, federal funds can be used to mitigate any resulting impact.

BOB ELDER, one of four members of the Lake County Historic Preservation Board which is working on a master plan, believes there are many development possibilities for Finntown and the Stray Horse Gulch area. Contingent on outside funding, he envisions creating a Finnish ethnic center that would focus on the mining, union activities, and cross-country skiing traditions these people brought to Leadville.

The nearby Denver City Mine, which Elder owns, could also be developed into a circa-1910 mining museum with displays of vintage mining equipment. The still-existing Comstock-style shaft house, which looks like a giant creature crouching over the shaft, is a good example of a once-prevalent design in which engine house and shaft were combined.

The anticipated Mineral Belt Bike Trail, grades for which have already been bulldozed, will give easy access to the whole historic area.

Mike Holmes optimistically estimates that with two more seasons of work, the EPA could be out of Leadville by late 1999 or 2000. As work is completed over the next two to three years, the process of delisting Leadville as a Superfund site could begin.

In an effort to coordinate remediation efforts, the involved parties have been meeting with county and city officials on a monthly basis.

The EPA has taken responsibility for remediation of areas for which no PRPs (Potentially Responsible Parties) could be determined. But much of the clean-up has fallen to ASARCO and Resurrection Mining Companies.

One of the foremost concerns of the EPA was lead exposure in residential neighborhoods. To address this problem, ASARCO introduced its Kids First Program in 1994.

Bob Litle, ASARCO’s Superfund Site Manager, indicated that response to this voluntary program has been very positive. Sixty-five to seventy percent of the community’s children were tested for blood lead, and although some elevated levels were found, they were only slightly above the national average. In taking action when it did, Leadville is ahead of many other cities in combating lead exposure not only from mine waste but also from such sources as leaded paints, pipes, and gasoline.

During the summer of 1997, ASARCO removed four mine waste piles with high lead content (Hope/Last Chip, Wolcott, and two Hibschle piles), incorporating them into the reclamation of the Hamm’s Mill site. Ten more piles are scheduled to be moved in the near future.

THE FEASIBILITY STUDY for the highly visible Apache Mill tailings (at the southern end of Harrison Ave.), should be finished in March, with remedial work to begin in the spring. Two lower ponds, which were created during World War II when the U.S. government remilled tailings, have already been moved and incorporated into a larger, upper impoundment. Work on the larger pond will probably involve grading, capping,and use of clean fill.

For the Colorado Zinc-Lead Mill and Western Zinc, Elgin, Union-Grant, and Arkansas Valley Smelter sites, ASARCO is doing feasibility studies to determine possible remedies for removal and disposal of such substances as asbestos and baghouse dust (metallic vapors that were filtered into 30 foot tall bags to be resmelted to extract remaining metals).

The orange-colored, acidic discharges from the Yak Tunnel, which originally earned Leadville its designation as a Superfund site, are being treated by a water treatment plant built in 1991 as a joint venture between ASARCO and Resurrection. The Yak Tunnel was constructed at the turn of the century to dewater operating mines. Now, the treatment plant, which first went on-line on February 28, 1992, is working at capacity.

Although the Oregon Gulch Tailings Pond is hidden from view, it became the scene of intense activity as Resurrection Mining Company began its Superfund remediation responsibilities. (The pond results from operations at the ASARCO-Resurrection Mill from about 1942-1956.) During the summer of 1996, heavy trucks removed tailings that had washed into the stream channel and hauled them back to the pond. In 1997, waste materials from the Colorado Zinc-Lead Mill in Stringtown were relocated to the same area.

Rick River, Resurrection’s Director of Reclamation, estimates that this summer, subject to final approval, 11,000 cubic yards of fluvial tailings will be removed from five poorly-vegetated, erosion-prone sites along lower California Gulch, and stream channels will be reconstructed where needed.

This sediment would also be placed on the Oregon Gulch impoundment. When completed, plans call for the impoundment area to be regraded to lessen slopes, and for an impermeable liner with cap to be placed over the entire pile. The top would be revegetated to give a meadow-like appearance, while rock and soil would be placed on the front and side slopes.

Since final remediation of the three-mile-long lower California Gulch is dependent on the upstream work, this will be the last area that Resurrection completes. Permanent stream bank stabilization and revegetation are scheduled for 1999, although temporary measures will be taken this year. River (rhymes with driver), estimates that all work will be done by the year 2000.

Of all Leadville Superfund areas, upper California Gulch is probably the most well-known because it was there that Oro City was located and the first mining operations in the region began. Work during 1995 and 1996 on the Garibaldi and Agwalt Mine sites consisted of reopening their portals and building collection systems to channel water into diversion ditches. A similar process of diversion will be done with several other mine waste piles, except for four acidic piles which will most likely be moved to one site, and capped.

Like many of the other heavily worked areas, the area around the A.Y. and Minnie mines is also devoid of vegetation, but the spoils are not very mineralized and have minimal impact on water quality. Because of its historic significance, little disturbance of the area is proposed. But a diversion ditch at the top of one slope could help minimize erosion.

The Mineral Belt Bike Trail will provide a close-up view of the historic upper California Gulch mining district. To widen the bike trail in a couple of narrow spots above the A.Y. and Minnie Mines, Resurrection would like to construct wooden cribbing to echo the old cribbing along the highway. The highway along the gulch may be relocated to the south, and the existing mine cribbing would then be allowed to fail naturally. To improve water quality, plans call for a sediment pond below the two mine sites, with wetlands placed along the stream.

River says that sixty percent of this work should be completed this year and the remaining forty percent next year.

Although slag (waste product from the smelting process) has been determined to be non-hazardous unless it is so fine it’s breathable, the railroad worked throughout last summer and into this year to remove the Harrison Avenue slag pile. The slag is being stored for future use as ballast to hold ties in place. With the huge coal-like black pile gone, the southern approach to Leadville and upper California Gulch has a whole new look.

STATE SENATOR KEN CHLOUBER has been one of the most vocal critics of the whole Superfund process: “EPA has done incredible damage to the community…. There are some two thousand mines on the east side of town. How can the removal of twenty to thirty mines help? … EPA has a place in our society, but not in Leadville. We are victims…. We’re a healthy community. EPA needs to leave Leadville with no strings attached. They need to get us off the Superfund list.”

On the other hand, Pete Moller, Professor of Environmental Technology at Colorado Mountain College, feels: “The clean-up could have happened a lot sooner if the studies hadn’t been stretched out so much. In the long run, I think Leadville is going to gain from the work being done. There will be some losses, mostly historical, but they will be more than compensated for by what is being achieved.”

Although outsiders may have been left with the impression that Leadville is an unhealthy place to live, few residents feel that way. Tim Ebuna, a teacher with the Lake County School District who lives just a few blocks from the Stray Horse Gulch clean-up, says: “We were up around the whole mess walking and stuff (before the clean-up). Occasionally there was a little dust on windy days, but it was definitely not detrimental to (the health of) our three sons.”

Given the nation’s growing awareness of environmental hazards, however, the clean-up in Lake County was inevitable. The only remaining question was who would determine the methods, and who would pick up the tab.

If Leadville is to remain a vital, healthy community into the next century, some change was and is necessary — since few people want to live in a museum-piece of a town.

Moreover, new residents and tourists are more likely to be interested in the highlights of Leadville’s history, not in the whole “dirty” story in minute detail.

Although the Environmental Protection Agency elicits a number of emotions from Leadville residents, most of them not positive, Mike Holmes, the down-to-earth Project Manager for the last three years, sums up his experience saying: “It’s been fun.”

Sharon Chickering has raised a family in Leadville for more than twenty years and has never felt their health was at risk. Today, she has nearly 21 linear feet of information in her library about the California Gulch Superfund Site — which certainly made it difficult for her to write a reasonably short article.