During World War II, dewatering of the Penn mine resulted in fish kills that essentially wiped out the salmon in the Mokelumne. As a result, EBMUD was required to maintain a fish hatchery at the dam, but, because there was no requirement that the utility maintain adequate river flows necessary for the fish to survive once they left the hatchery, the kills recurred.

In 1977, major fish kills because of mine wastes in the Camanche reservoir resulted in the issuance of a Cleanup and Abatement Order to New Penn Mines, the owner of the mine. The order was ignored, as were most subsequent orders.

Other attempts to deal with New Penn Mines also failed, and in March 1979, EBMUD, the state Department of Fish and Game (DF&G), and the Central Valley Regional Water Quality Control Board agreed to a joint cleanup of the mine discharges. They built surface diversion ditches and a series of ponds along Mine Run creek above the point where it drains into the river.

The potential problem of contamination of groundwater in the 55,000 linear feet of underground shafts at the mine, with a capacity of perhaps 30 million gallons, was not addressed. As Dennis McCord, current supervisor at EBMUD’s Pardee center says, “Our contention is that there is no seepage of toxins from Penn through dikes or groundwater into Camanche. We think that the only problem is when the containment dikes overflow due to heavy rains.”

Such overflows, both controlled and uncontrolled, began in 1979, the same year the water quality board rescinded its Cleanup and Abatement Order noting that EBMUD had “removed the accumulated muds from Oregon Bar and constructed Mine Run Dam which effectively prevents further contributions of zinc and copper to Lake Camanche.”

Despite that assurance, the spills continued on 24 percent of all days throughout the next 10 years, with more than 42 million gallons going over the dam some years.

Throughout the ’80s, pressure mounted to control the toxic discharges from Penn Mine. EBMUD continued to point out that it was not the owner of the mine, but requests for materials and threats of fines against the absentee owner were ignored.

Eventually, the California Sportfishing Protection Alliance filed a complaint with the water quality board charging EBMUD with violating the law by operating outside waste discharge requirements and without the necessary permits. The utility then quietly filed for a waiver from the Waste Discharge Requirements and an exemption from the provisions of the Toxic Pits Cleanup Act (TPCA), which would mean it would avoid having to conduct a hydrogeological assessment report (HAR). Penn Mine was not mentioned in the waiver request.

Although hotly contested by the various fishing and conservation groups, downstream users, and the San Joaquin County Board of Supervisors, the water quality board granted the exemption and waiver. And, in late 1990, EBMUD filed a request with the U.S. Environmental Protection Agency to have the mine removed from its list of toxic waste sites. The same local groups that fought the waiver subsequently accused the utility of trying to make an end run around federal anti-pollution laws.

EBMUD, however, constantly reiterated its position that it did not own the mine and, therefore, was not responsible for the pollution from it. Nevertheless, the state’s attorney general had held in numerous cases that “dischargers are the persons who now have legal control of the property from which such drainage arises. By failing to take action which is within their legal power to halt the defilement of the drainage or to render it harmless with treatment before it departs their property, (they) are responsible for the deleterious discharge.”

The attorney general also noted that, “the fact that the persons who conducted the operations which originally produced the harmful material have left the scene does not free from accountability those permitting the existing and continuing discharge of the material into waters of the State.”

Eventually, in the face of continued complaints by the DF&G and the California Sportfishing Alliance, EBMUD began a program to protect the Mokelumne River Fish Installation, including the injection of potassium permangante to reduce hydrogen sulfide, as well as establishment of an in-reservoir outlet and better management of the outlet and its withdrawal system.

But the biggest problem, that of adequate river flows, remained. Until the utility agreed to release water from the dams, they argued, fish in the hatchery were doomed once they left it.

The Committee to Save the Mokelumne argues that the best short-term solution is dilution of the contaminants with increased riverflows and higher reservoir levels. It points out that, “although millions of Californians drink treated delta water (considered lower quality), EBMUD has consistently demanded only ‘pure Sierra water.’ It has refused to seriously consider allowing part of its allocation to flow down the Mokelumne to be recaptured from the delta,” fearing that its own water supply would run short.

Meanwhile EPA has listed the Penn Mine on the short list of cleanup areas under the Clean Water Act. This means, among other things, that individual control strategies must be developed to reduce discharge of toxic pollutants from point sources.

EBMUD, however, points out that, under the law, dams and dikes cannot be considered point sources.

The water quality board recently received $330,000 ($100,000 of it from EBMUD) to study the problem at Camanche. Of that amount, $70,000 was used to drill wells to investigate the potential groundwater pollution. The entire cost of the study is less than that of a full HAR, which can cost more than $500,000, and the Committee to Save the Mokelumne accuses the utility of trying to avoid undertaking the larger assessment, which, presumably, would reveal the extent of groundwater contamination at the site.

McCord defends EBMUD, however. “This is where (the committee’s) argument falls apart. No one has found a groundwater contamination plume. There are as of this year five groundwater monitoring wells looking for contamination. We are doing it at our own lab in Oakland, and the results are public information.”

Critics argue that EBMUD is not really looking for a groundwater contamination plume, however. According to McCord, the worst case scenario “would be a definite conclusion that groundwater contamination is occurring and that it is a function of our efforts to contain surface run-off, with heavy metals leaching to the groundwater. It may cost $100 million to clean up the surface waters, but it could cost $1 billion or more to clean up the groundwater.”

That being the case, McCord uses the old EBMUD argument once again — “our position is still that the contaminated element is off our property and the fact is the runoff crosses ours.”

However, the utility has compiled a list of alternative strategies to control acid mine drainage, but it states that source mitigation measures “would necessarily be the responsibility of the owners of New Penn Mine, Inc.” Unfortunately, the company has gone bankrupt, and its owner has died. Alternatively, the utility argues that “options could be undertaken by the current owners of new Penn Mine, by the state of California or by the EPA.” McCord, however, admits that “they will probably end up holding our feet to the fire.”

The first alternative listed by EBMUD is the “No Action Alternative,” but it does recognize that the California Administrative Code would require the closure of surface impoundments and place requirements on the ability of the system to handle 25-year event 24-hour storms that may not be met by existing structures.

It also notes that although public utilities are now exempt from the provisions of Proposition 65, which requires cessation of discharges of chemicals known by the state to cause cancer or reproductive toxicity (including lead, arsenic, cadmium and chromium, all of which occur in Penn Mine wastes), the legislature is expected to soon eliminate that exception.

The second alternative is source control, which would involve removal of tailings and treatment of standing water, followed by closure of the ponds. Although this would solve the problem, it would be expensive even if a suitable landfill for the tailings could be found. Even the conservative EBMUD estimate of the cost of this option is $140 million; and a cheaper version, involving on-site disposal is $80 million.

A freshwater lagoon in California.

Alternative three would be to install a permanent packaged water treatment plant at Mine Run reservoir which would be able to treat expected discharge for rainfalls of less than 36 inches per year. Such a plant, treating 200 gpm with lime, flocculation, sedimentation and sludge dewatering, would run for three to six months a year.

However, it would not meet the regulatory requirements of Title 23 regarding the closure of the mine operations, so, according to EBMUD, “the owners of Penn Mine (now apparently non-existent) would still be obligated for final closure of the mine workings. The owners would also be responsible for the costs of the water treatment facility,” $400,000 initially and $210,000 annually for operation.

The fourth alternative, “improved operation of existing system,” is the one officially favored by the utility. Its report on the alternatives states: “Assuming that EBMUD will be responsible for the continued operation of Mine Run Reservoir, and that the reservoir will not be closed under the provisions of the Toxic Pits Cleanup Act because of unacceptable environmental impacts, this alternative will incorporate best management practices to minimize releases of acid mine drainage to the Camanche reservoir.”

EBMUD proposes to begin with monitoring of water from Mine Run reservoir and possible seepage from mine shafts and diversion structures. It also proposes preparation of an overall water balance showing inflows and outflows during a one-year period, while conceding that “it is difficult to provide an accurate water balance because of lack of data …”

This alternative, though, seems unlikely to satisfy either the government entities or the private groups that are concerned with the Penn Mine problem. In view of this, McCord says, “I fully expect some sort of plant — perhaps a lime plant, because the whole thing is very acidic. Maybe we can neutralize it with lime slurry.”