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Spanish Mine Water Quality Remediation Project

Adit #1 treatment cell with underground leach field

December 2011 – Rick Cunningham, Lands Manager

Adit One

Adit #1: A trickle of water emerges from what was once a mine portal in the 1850's.

– Located in Nevada County  near the small town of Washington, Spanish Mine  was originally a gold mine founded in the late 1800’s during the Gold Rush.

Over the years, the mine changed ownership multiple times. When the ore finally ran out, the underground operations were closed and multiple entrance portals, called “adits”, were buried. At some point, most of the timber on the property was harvested, but wasn’t replanted.

Soper-Wheeler purchased this environmentally damaged property in 1996 as cut-over timberland with the intent of rehabilitating the forest and practicing long-term sustainable forestry.

Almost immediately after we completed the purchase, we were sued by The California Sportfishing Protection Alliance (CALSPA) under the Clean Water Act for illegal discharge to waterways from the old mine works, although we had nothing to do with the mining that had occurred 140 years prior on the property.

Grassland created by the discharge of Adit #1

Grassy area on top of a road created by the discharge of Adit #1

After a protracted legal battle, we settled for an undisclosed sum with CALSPA, not a penny of which went towards the clean-up of the abandoned mine.

Spanish Mine “discharge” water actually meets Federal drinking water standards, however it does not meet “waste discharge” requirements. Amazingly, some of the numerical standards required for “waste discharge” are 100 times cleaner than drinking water standards. Additionally, there is no empirical evidence whatsoever that Spanish Mine’s “discharge” is harming fish or any other aquatic species. Unfortunately none of this matters when it comes to compliance with Federal law.

Accordingly, we were ordered by the California Regional Water Quality Control Board to clean up the water that was entering the tributaries of the South Yuba River from underground sources to EPA standards. Specifically two adits, #1 and #3, were identified as discharge sites.

Unfortunately, the Clean Water Act was designed for industrial facilities with process controls, not remote historical mine sites that behave chaotically. Because of this, real-world solutions are extremely limited, and none of those solutions meet EPA treatment standards.

In our case, the amount that actually reached the local creeks was very small: about the same flow as a few garden hoses, with most of the metals dropping out along the way. The metals detected in the water are at the very minimum treatment threshold levels for “constituents of concern” mandated by the Clean Water Act.

Straw bales were placed in the grassy area to create an aerobic test cell

Straw bales were placed in the grassy area to create an aerobic test cell

Wanting to clean up the site, we worked cooperatively under direction of  the Central Valley Regional Water Quality Control Board with help from Vestra Resources, our consulting engineer, over a number of years.

Meanwhile, CALSPA intervened in the process multiple times, causing unnecessary delays to the clean-up while increasing costs to both us and to the State of California.

Our best guess is that CALSPA’s counterproductive delay tactics were likely designed to enhance settlements from lawsuits in numerous other cases they have filed.

At one point during a hearing, a CALSPA lawyer publicly admitted to Charles Hoppin, Chairman of the California State Water Control Board, that no CALSPA representative had ever visited the Spanish Mine site.

We are now currently working under a cease and desist order from the California Regional Water Quality Control Board, which prevents further lawsuits to us regarding the matter.  Under that order, Soper-Wheeler is also required to establish a five-year plan that would reduce metallic constituent levels in the “waste discharge”.

We chose to address Adit #1 first: this site was initially running onto a dirt road that that developed into a grassy area over time.  The grass was essentially treating the effluent from the adit. Unfortunately, some runoff was still making its way above ground to the creek below, and although the metals had mostly dropped out, the grassy area did not conform to the stringent requirements of the Clean Water Act.

Top view of anerobic pilot cell at Adit #1

Top view of anaerobic pilot cell at Adit #1

The idea of the clean-up was to design a fully contained man-made wetland that would mimic the grassy area to aerobically drop out some of the metals. This would be followed by second containment filled with wood chips and other natural materials to anaerobically remove the remaining metals while balancing the pH levels in the water.

First we had to prove that the concept would work. We installed straw bales into the grassy area to slow and contain the water. This was our “aerobic pilot cell”.  After a year of flow monitoring and chemical analysis, the results confirmed that most of the iron dropped out, and other metal levels decreased as well.

Encouraged by the results, we installed the secondary “anaerobic pilot cell” filled with a mixture of wood chips, straw, and manure to get the anaerobic process going. After a second year of flow monitoring and chemical analysis, this too proved a success, lowering the levels below the EPA thresholds, however there was still no practical way to achieve water 100 times cleaner than drinking water in order to meet EPA discharge standards.

The end of 2011 was the deadline to get the Adit 1 full-scale treatment in place. With two years worth of data from the two pilot cells, we designed a larger version of what we had tested. To meet the EPA standards, we worked with Regional Water Quality to include a leach field so the treated waters would not be discharged into the creek, thus reliving us from the “cleaner than drinking water” standard.

Adit #1 treatment cell with underground leach field

Adit #1 treatment cell with underground leach field

The result is what looks like a small rock and plastic-lined pond where the grassy area once was. This pond will eventually fill  in with marsh plants and other vegetation and end up looking similar to a natural wetland, functioning as our test cells and the original grassy area did. The water will slowly filter through this artificial wetland, dropping out metals as it goes. Eventually it will make its way to the other end where it enters into the underground leach field. This treated water then percolates into the ground, and no water will be discharged into the creek.

The new artificial wetland will be given time to naturally develop and we will continue flow monitoring and chemical analysis testing for some time to come before this portion of the project is completed.

Adit #3 will be our next challenge in 2012: it is in a much more difficult location, and it remains to be seen how various regulatory agencies will interact in our efforts to clean up the site.

Click images to enlarge

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