Abandoned Mine Remediation on CSLC Lands
February 2012
The California State Lands Commission (CSLC) works internally, as well as cooperatively since 2003 with the California Department of Conservation’s Office of Mine Reclamation (OMR), to inventory and remediate abandoned mine hazards on State School Lands in the California desert. Many of these abandoned mines are nearly 100 years old and existed prior to the State’s acquisition of the lands and enactment of State laws requiring reclamation of lands impacted by mineral exploration or production. Although many mine features, which include vertical shafts and horizontal adits, are used as habitat by wildlife, such as bats, desert tortoise, rodents, etc., some features such as vertical shafts may pose a physical hazard to the public that recreates on State lands in the California desert and can also entrap animals. Preliminary assessments have also been conducted at multiple abandoned mine sites on CSLC lands to look for potential chemical hazards typically associated with some types of mining activity.
Addressing physical hazards associated with abandoned mines is a complex process that includes remedies ranging from signage to permanent closure. Upon discovery of a mine feature that may pose a hazard, CSLC and/or OMR staff install warning signs to “Stay Out and Stay Alive,” which advises the public of the many dangers associated with old abandoned mines. Prior to any mine closure, surveys are conducted to determine the biologic and historic attributes to determine along with the physical characteristics, what closure technique may be physically possible and best suited for each feature. The CSLC staff consults with the California Department of Fish and Wildlife (CDFW) and the State Office of Historic Preservation’s State Historic Preservation Officer (SHPO) with detailed information and closure plans. The Commission has determined projects to be exempt under the California Environmental Quality Act (CEQA) when CSLC staff receives concurrence from the CDFW and SHPO that the closure techniques would not significantly impact wildlife or historic resources.
For example, when internal or external surveys reveal the presence of either significant biological or historical resources, bat gates or cupolas have been built to protect the public and wildlife. Bat gates conforming to the standards of Bat Conservation International can be installed on horizontal adits such that bats, owls, desert tortoise, and other animals can continue to use the mines for habitat while precluding and safeguarding the public. Similarly, for vertical shafts, a cupola (or basically a box made of steel angle iron) can be installed over the shaft allowing continued wildlife access. Both closure techniques protect and preserve historic resources, and can be designed in a way to allow biologists and archeologists to perform surveys or geologists to prospect for a valuable mineral deposit
Mine shafts that are relatively shallow and have no horizontal workings generally provide poor wildlife habitat, but may still pose a fall hazard to the public and wildlife. Such shafts typically have little historic value in comparison to the public hazard they may pose. When shafts such as these have the original waste rock dump adjacent to them, the CSLC/OMR staff has contracted for a small front end loader to backfill the shaft with the original waste rock. When waste rock is not available, a polyurethane foam plug may be used that is later covered with native rock and soil to protect the foam from sunlight and obscure the original location.
Some mines may not be suitable for bat gates, cupolas or foam plugs due to unique circumstances or they cannot be reached by vehicle. Wire fences are commonly employed on these mine features or as a temporary measure until a more permanent solution can be sought.
In August 2009, OMR completed an inventory of all abandoned mine lands managed by State agencies including that of the CSLC. CSLC lands were identified as having approximately 143 sites with more than 1,200 individual mine features on them and were ranked for the physical and chemical hazard that they may pose. Since then, CSLC staff has been inventorying those sites that were ranked by OMR as posing the greatest physical hazard to the public. Warning signs are being installed as plans are formulated for additional surveys so that more permanent closure techniques can be used. Unfortunately, many of these signs are quickly stolen or vandalized. More recently, in the later part of 2011, CSLC staff inventoried and installed warning signs at the Leiser Ray, New Trail and Shadow Mountain Mines in San Bernardino County and at the Baxter Mine in Inyo County. In early 2012, wildlife surveys were completed by Brown-Berry Consulting and CSLC staff at the Leiser Ray Mine and work has begun to determine appropriate closure measures for the 13 shafts and adits located there. Closure activities are anticipated in the spring and fall of 2012.
The following list is a summary of many of the more prominent mine features the CSLC and OMR have safeguarded on State school lands with bat gates, cupolas, foam plugs, fences, and signage. Much work remains to be performed. At some sites, some of the mines were able to be closed, while others require permanent solutions due to challenges such as difficult access. Some of the names used are for mines located on adjacent federal or private lands as mine sites can contain dozens of mine features located with a complicated patchwork of ownership. In other cases, a name is used proximal to a nearby community as many of the mines were simply prospects and never were given formal names. The CSLC is constrained to work only of lands it manages.
Mine Name |
County |
Type of Closure |
|---|---|---|
| Crown Uranium Mine | Imerprial County | Two Bat Gates |
| Golden Queen Shafts | Imerprial County | Backfill |
| Guadalupe Mine | Imerprial County | Foam Plug |
| Turtle Mine | Imerprial County | Fence |
| Rosamond Mine | Kern County | Backfill |
| Standard Hill Mine | Kern County | Backfill |
| Golden Bee Mine | Riverside County | Bat Gates |
| Arnold Edward Mine | San Bernardino County | Fence |
| Calico Mountains | San Bernardino County | Backfills |
| Fry Mountains | San Bernardino County | Backfills and Fence |
| Gold Standard Mine | San Bernardino County | Cupola |
| Iron Horse Mine | San Bernardino County | Fence |
| Los Padres Mine | San Bernardino County | Foam Plug, Backfill, Fence |
| Pacific Fluorite Mine | San Bernardino County | Cupola |
| Rusty Gold Mine | San Bernardino County | Fence and Backfills |
| Scouts Cove Mine | San Bernardino County | Foam Plug |
| Shadow Mountain Mine | San Bernardino County | Fence |
| Ship Mountain Mine | San Bernardino County | Bat Gate and Backfills |
| Stone Cabin Mine | San Bernardino County | Backfill |
| Trade Rat Mine | San Bernardino County | Backfill |
| Trade Rat Mine | San Bernardino County | Backfills |
 CSLC/OMR Abandoned Mine Warning Sign Installed at |
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Fence Installed at the Trade Rat Mine in San Bernardino County in May 2004. Mine was Backfilled with Waste Rock in October of 2007 |
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Wildlife Survey Conducted by Dr. Pat Brown |
Bat Gate with Tortoise Door at Mohawk Hill |
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Bat and Owl Compatible Cupola Installed Over Gold Standard Mine |
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Scouts Cove Opal Mine - May 2001 |
Scouts Cove Opal Mine - April 2003 |
Plugging of Mine Shaft with Polyurethane Foam |
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For further information please contact Greg Pelka of the Mineral Resources Management Division at (562) 590-5227 or Cy Oggins, Chief of the Division of Environmental Planning at (916) 574-1880.
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From Voice Phone 1-800-735-2922