water percolates through the leavings from the mining and dissolves the previously stable metals and other toxic chemicals.
There are Super Fund sites that were once mines that have plants built that gather and process the dangerous leached fluids and extract the toxicity, this applies to other former metal mines (copper for instance). The "product" of the mediation plants separates the toxic from the leached fluid that is then landfilled and stable and not bleeding toxins into the environment.
The process is very expensive, not a net money maker, and the situations very common (and may not have the concentrated toxins where collection and processing is feasible).
Your not nuts but there is not a practical solution in many cases and one that is economically feasible rare. When such a process is undertaken, the process rather than being a money maker is the low cost remediation to an existing problem where there is a feasible means to gather the runoff.
A good example is the Iron Mountain Super Fund site near Redding, CA where a water treatment plant was built to treat toxic runoff as part of remediation:
>>Iron Mountain Mine, also known as the Richmond Mine at Iron Mountain, is a mine near Redding in Northern California, USA. Geologically classified as a "massive sulfide ore deposit", the site was mined for iron, silver, gold, copper, zinc and pyrite intermittently from the 1860s until 1963. The mine is the source of extremely acidic mine drainage which also contains large amounts of zinc, copper and cadmium. One of America's most toxic waste sites, it has been listed as a federal Superfund site since 1983.[1]
History
The site was mined by the Mountain Copper Company, Ltd., both underground using open stope mining techniques and at the surface in the form of open pit and sidehill mining. As a result, the mountain fractured and mineral deposits were exposed to oxygen, water and certain bacteria, resulting in acidic mine drainage. Though mining operations were discontinued in 1963, underground mine workings, waste rock dumps, piles of mine tailings, and an open mine pit still remain at the site. The mine was designated a Superfund site in 1983 and a water treatment plant was built in 1994. In 2000 the government reached a settlement with Aventis CropScience (now part of Bayer) for the long-term funding of the cleanup efforts.[1]
Location and drainage
Collecting drainage in the Iron Mountain Mine
The mine is located at 40°40?20?N 122°31?40?W in the Klamath Mountains of Shasta County, about 9 miles northwest of Redding. The mine area is drained by several creeks which ultimately enter the Spring Creek Reservoir, formed by the Spring Creek Dam, and finally the Keswick Reservoir formed by a dam across the Sacramento River. This reservoir is a major source of drinking water for Redding.
Historic mining activity at the site has fractured the mountain, exposing minerals in the mountain to surface water, rain water, and oxygen. When pyrite is exposed to moisture and oxygen, sulfuric acid forms. This sulfuric acid runs through the mountain and leaches out copper, cadmium, zinc, and other heavy metals. This acid flows out of the seeps and portals of the mine. Much of the acidic mine drainage ultimately is channeled into the Spring Creek Reservoir by creeks surrounding the mine. The Bureau of Reclamation periodically releases the stored acid mine drainage into Keswick Reservoir. Planned releases are timed to coincide with the presence of diluting releases of water from Shasta Dam. On occasion, uncontrolled spills and excessive waste releases have occurred when Spring Creek Reservoir reached capacity. Without sufficient dilution, this results in the release of harmful quantities of heavy metals into the Sacramento River. Approximately 70,000 people use surface water within 3 miles as their source of drinking water. The low pH level and the heavy metal contamination from the mine have caused the virtual elimination of aquatic life in sections of Slickrock Creek, Boulder Creek, and Spring Creek.
The drainage water from the Iron Mountain Mine is the most acidic water naturally found on Earth; some samples collected in 1990 and 1991 have been measured to have a pH value of -3.6.[2] Water temperatures as high as 47°C have been measured underground.
The drainage water endangers fish, including winter-run Chinook salmon, a federally listed endangered species that spawns in the Sacramento River. Salmon kills have been noted since 1899.
from wiki: https://en.wikipedia.org/wiki/Iron_Mountain_Mine
= new reply since forum marked as read
