«FINAL ACTION MEMORANDUM FOR THE NON TIME-CRITICAL REMOVAL ACTION IN THE CHALK CREEK WATERSHED SALIDA RANGER DISTRICT SAN ISABEL NATIONAL FOREST ...»
FINAL ACTION MEMORANDUM
FOR THE NON TIME-CRITICAL REMOVAL ACTION IN THE
CHALK CREEK WATERSHED
SALIDA RANGER DISTRICT
SAN ISABEL NATIONAL FOREST
Caring for the Land and Serving People Printed on Recycled Paper
Page 2 of 8
FINAL ACTION MEMORANDUM
NON TIME-CRITICAL REMOVAL ACTION IN THE
CHALK CREEK WATERSHEDSalida Ranger District San Isabel National Forest I. PURPOSE The purpose of this FINAL ACTION MEMORANDUM is to execute a non time-critical removal action at abandoned mine lands (AML) sites located in the Chalk Creek Watershed.
The primary objective of the non-time critical removal action is to reduce impacts of mine waste rock, mine tailings, and adit discharge on human health and the environment. It is the intent of the proposed remedy to minimize continued degradation of surface water in the Chalk Creek Watershed as a result of continued leaching of metals from the AML sites, and to make incremental improvements to the watershed. The Chalk Creek Watershed is located on the Salida Ranger District of the San Isabel National Forest near St. Elmo, Chaffee County, Colorado.
This action is being taken pursuant to the USDA Forest Service’s Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA; 42 U.S.C. 9604) authority and Executive Orders 12580 and 13016 for lands under the custody, jurisdiction or control of the USDA Forest Service.
This action memorandum authorizes the non time-critical removal action in accordance with the National Contingency Plan (40 CFR 300), US EPA Office of Solid Waste and Emergency Response Guidelines (EPA 540-R-93-057) and USDA Forest Service policy and procedures.
II. SITE CONDITIONS AND BACKGROUNDSite Location All of the AML sites addressed in this FINAL ACTION MEMORANDUM are situated within the Chalk Creek drainage basin, within five miles south of the former mining town of St. Elmo.
The Chalk Creek watershed encompasses the Chalk Creek Mining District (also known as Alpine, St. Elmo, Forest City, Hancock, Romley, and Mineral Hill), located in the upper reaches of Chalk Creek. The Chalk Creek mining district is located on the Salida Ranger District of the San Isabel National Forest in western Chaffee County approximately 20 miles southwest of Buena Vista, Colorado. County Road (CR) 162 from United States Highway 285 provides access to the mining district and to St. Elmo. Various Forest Service roads, mine roads, and trails from St. Elmo access most of the mines, which are located at elevations ranging from approximately 10,000 feet to 11,400 feet.
Chalk Creek and its tributaries drain the eastern slopes of the Collegiate Range with Chalk Creek entering the Arkansas River 10 miles south of Buena Vista. The sites’ topography and
Site Descriptions Stonewall Mine The Stonewall Mine site is the southernmost and most upstream site of the Chalk Creek AML sites (south of the ghost town of Hancock) and is situated along the west side of Chalk Creek. At the site, Chalk Creek flows to the north from an elevation of approximately 11,250 feet. The Stonewall adit discharges into Chalk Creek. Several waste rock piles are located over a large area on the northeast side of the site, some adjacent to Chalk Creek.
Flora Bell Flora Bell is located between the ghost towns of Hancock and Romley and straddles CR 295 which originally served as a railroad line. The site is on the flank of a ridge at an estimated elevation of 10,900 feet, approximately 1,000 feet east of Chalk Creek. Waste rock piles from the Flora Bell adit occur on both sides of CR 295. The Flora Bell mine site includes an adit draining water.
Mary Murphy 1400-Level The Mary Murphy 1400-Level is located on the west side of Chrysolite Mountain and approximately 250 feet east of Pomeroy Gulch, adjacent to Forest Road (FR) 297. Site features include waste rock pile one and waste rock pile two, also identified as the “ore pile”. Waste rock pile one is the largest pile in Pomeroy Gulch. Effluent from the portal drains into a steep, braided channel that flows north of the historic tram station and the ore pile. The water then flows freely along FR 297 prior to entering Pomeroy Gulch.
Chalk Creek Shaft The Chalk Creek Shaft is located on the west side of Chalk Creek immediately east of FR 294 and across from the consolidated tailings pile below the Golf Tunnel. Site features include a flooded shaft, a waste rock pile and the remains of a small head frame which is still standing.
Waste rock is located adjacent to Chalk Creek.
Chalk Creek North The Chalk Creek North site consists of an adit and associated waste rock pile located on the west side of Chalk Creek, northeast of the Chalk Creek Shaft site. This area is characterized by steep slopes and dense vegetation. The waste rock pile is the largest and most distinct mine feature on the slope of this mountain. The remains of an ore hopper are perched on this steep, long, and thin waste rock pile.
St. Elmo Queen The St. Elmo Queen is located on the lower slopes of a ridge on the west side of Chalk Creek, less than a quarter-mile northeast of the Chalk Creek North site. Site features consist of a collapsed/caved (and discharging) adit, and a waste rock pile.
Gold Dust The Gold Dust is located on the north side of Chrysolite Mountain approximately 0.75 miles from St. Elmo. The Gold Dust site includes a waste rock pile and a closed adit that has ephemeral discharge. The mine features are apparently on a patented claim; however, exhaustive
Lady Murphy 1100-Level The Lady Murphy 1100-Level is on the north side of Chrysolite Mountain, about 140 feet below the Iron Chest Mine, just below tree line at an elevation of 11,100 feet. Two waste rock piles and an adit with ephemeral drainage are at the site.
Iron City Mill Tailings The Iron City Mill site is located near the town of St. Elmo, adjacent to CR 292. The tailings from the Iron City Mill were crushed and pumped from the mill down to the site located approximately 400 feet to the northeast. Surface water drainage from uphill flows through a culvert, under County Road 162, and across the tailings pile.
The United States Environmental Protection Agency and various State of Colorado agencies have completed various cleanup actions on private lands in this historical mining district.
Cleanup of these sites on NFS-managed lands will compliment the environmental benefits realized from these previously-completed projects.
III. THREATS TO PUBLIC HEALTH OR WELFARE AND THE ENVIRONMENT,
AND STATUTORY AND REGULATORY AUTHORITIES.
The Engineering Evaluation/Cost Analysis (EE/CA) completed in 2009, documents waste rock containing elevated levels of metals, which are above residential soil screening values, and therefore may pose a risk to human and ecological receptors. Mine water samples results indicated elevated levels of metals which provide an on-going source to the degradation of the water in Pomeroy Gulch and Chalk Creek.
Given the uncontrolled nature of the sites, there is a high potential for direct exposure of people to the heavy metals found at the sites. Because of the location of the area, the sites are also used for recreational activities. Heavy metals associated with the waste piles can affect human health/wildlife through inhalation of dust or ingestion of solids and water.
Direct contact with waste material at ground surface is a primary concern at the sites. However, there is run-off and erosion from the sites which increases leaching and mobilization to surface waters down gradient from the associated piles. Wind dispersal of the contaminants also occurs.
These locations are subject to harsh winters with a pronounced spring snowmelt. During normal seasonal snowmelts hazardous substances will continue to migrate off-site and into Pomeroy Gulch and Chalk Creek.
The Colorado Department of Wildlife operates a fish hatchery on Chalk Creek a short distance above its mouth on the Arkansas River. In the past, adit discharges from upstream mines have contributed to fish kill at the hatchery and in Chalk Creek, as well as degrading the water quality in the Arkansas River.
The Forest Service has CERCLA authority and is designated as “lead agency” for lands under its jurisdiction and control at non-National Priorities List sites. No other appropriate response
IV. ENDANGERMENT DETERMINATIONActual or threatened releases of hazardous substances, pollutants, and contaminants from this site, if not addressed by implementing the response action selected in this Action Memorandum, will continue to endanger public health, welfare, and the environment.
V. PROPOSED ACTIONS AND ESTIMATED COSTSProposed Actions The EE/CA evaluated various removal action alternatives. Coupled with consideration of comments received from site stakeholders, these alternatives form the basis for the selected
removal actions presented in the summary table below:
Removal actions at the sites will comply with all of the substantive provisions of Federal and State ARARS to the extent practical considering the exigencies of the situation. USEPA notification and State of Colorado involvement was obtained through the ARARs process (as described in the Forest Service Guide to CERCLA and consistent with the NCP at 40CFR300.400(g) and 515(h)(2)). No federal, state, or local permit shall be required for any removal action occurring on-site pursuant to 40CFR300.400(e)(1) (as codified at 42U.S.C.
Project Schedule It is anticipated that the proposed actions in the Chalk Creek Watershed will begin in the summer of 2009.
VI. EXPECTED CHANGE IN THE SITUATION SHOULD ACTION BE DELAYED ORNOT TAKEN If no action is taken to remove and/or control the identified wastes and isolate them from the public and environment, the sites will continue to degrade and present a risk to public health, welfare, and the environment.
Heavy metal contaminants will continue to migrate from the sites with ongoing impacts to water quality in Pomeroy and Chalk Creeks.
VII. OUTSTANDING POLICY ISSUESThis action memorandum is issued in accordance with USDA Forest Service policy. There are no outstanding policy issues presented by this removal action.
VIII. ENFORCEMENT The USDA Forest Service is the lead agency (40 CFR 300.5) for this action. In this role, the USDA Forest Service is authorizing and implementing this action.