Manning Canyon
Manning Canyon is located in the Mercur Mining District, adjacent to the West Mercur and Fivemile Pass Mining Districts. The Mercur District was first organized in 1870 as the Floyd Mining District when silver lode discoveries were made. As time went on, gold became the primary commodity produced, causing a production or mining boom from 1898 through 1912. Mines located in the southern Oquirrh Mountains have also produced precious and base metals and clay.
In 1890, the Manning Mill was built to treat ore from the Mercur vein by pan amalgamation. The Manning Mill was remodeled in the summer of 1890 to process ore by the cyanide process. From 1890 to 1900 the crude ores mined at Mercur, Utah, 5 miles northwest of Manning, were transported by team and wagon and later by a privately owned railroad, and were leached in tanks by percolation with solutions of potassium cyanide. The mill expanded to 50 tons daily, then to 100 tons in 1893, to 200 tons in 1896, and then to 500 tons. Following construction of the Golden Gate Mill in 1898, the Manning Mill ceased treating Mercur ores and was used to process tailings. In 1933, a second mill was constructed at the Manning Mill Site to re-treat the estimated 455,000 tons of tailings in large dumps. From September 1934 to July 1936, an average of 536 tons of material (both tailings and crude ore) were treated per day. In addition to re-treating the tailings dumps left by the operations of the prior Manning Mill, the second Manning Mill operated as a custom plant to treat crude ores from Mercur and some ores from outside the Camp Floyd Mining District. After this second mill completed re-treatment of all the Manning "dumps," the mill was relocated in 1937 to Mercur.
Much of the private land in the surrounding areas includes patented mining claims from the late 1800s and early 1900s. Clay mining on these private lands remains active today. Private land located to the south is used for agricultural purposes, including wheat fields approximately 1.8 miles southeast of the Site. The small town of Fairfield is located 3.5 miles southeast of the Site. The Site has a history of recreational use. Purchased by its current owners in the 1950s, the private portion of the Site hosted national motocross events in the 1970s. Since then, off-road vehicle users and other recreational users have frequented the Site. March through September are high use months, usually receiving six to 10 vehicles per day with multiple passengers. The winter months receive less visitors. The BLM Salt Lake Field Office estimates an annual visitation of approximately 1,050 by tourists and locals. All terrain vehicles (ATVs), bicyclists, campers, and youths shooting paintball guns have been observed on the tailings deposits within the Site.
CURRENT ACTIONS
BLM completed the design plans and specifications using the Bureau of Reclamation’s Provo office. Other ongoing activity includes funding requests and negotiations with potentially responsible parties. A construction contractor, the Opal Group, was selected and Phase I of the work will begin during 2002. Phase I consists of constructing run-on controls and removal and consolidation of the upper tailings into the repository area. Phase II, to be conducted in 2003, will consist of ongoing construction of the repository and cap. Phase III, to be conducted in 2004 will consist of removal of the lower tailings area near the railroad right of way and placement into the repository. The Utah Department of Health was consulted on several occasions and was been sent sampling plans, preliminary assessments and the EE/CA for review and comment. The Utah County Health Department has been consulted for information on the Fairfield water supply. The State and County will be involved in construction of the remedy for the Site. The County and Utah Department of Transportation have been involved in review of design and construction aspects concerning improvements to the County road and other road access.
PROPOSED ACTIONS AND ESTIMATED COSTS
The EE/CA presented a study of the nature and extent of contamination at Manning Canyon, removal action objectives and action levels, a brief risk assessment and various alternatives to remedy the health risks. The overall goal of the response alternatives evaluated in the EE/CA is to reduce the release and threat of release of arsenic, mercury, and lead from the Manning Canyon Site, thereby reducing risks to human health and the environment. The alternatives were screened based on effectiveness in reducing risk, implementability and cost. A preferred alternative of an on-site repository was selected. The EE/CA has been prepared in accordance with the criteria established under the CERCLA, and sections of the National Contingency Plan (NCP) applicable to removal actions (40 CFR 300.415 (b)(4)(i)). The EE/CA is also consistent with EPA guidance document, Guidance on Conducting Non-Time-Critical Removal Actions Under CERCLA. The EE/CA removal action objectives were: *Reduce or eliminate the release of arsenic, lead, and mercury from the Manning Canyon mill site via surface water during flood events. *Reduce or eliminate the release of arsenic, lead, and mercury from the Manning Canyon mill site via surface water to ground water pathways. *Reduce or eliminate the release of arsenic, lead, and mercury from the Manning Canyon mill site via soil to air pathways. *Reduce or eliminate the release of arsenic, lead, and mercury from the Manning Canyon mill site via soil to ground water pathways. *Reduce or eliminate the potential for exposure to humans and wildlife from direct contact, ingestion, or inhalation with contaminated surface soils.
- Conceptual designs were developed for each of the four removal alternatives, and an opinion of probable
cost was prepared for each.
Estimate Cost of Reclaiming
On-Site Repository and Surface Water Diversion (Selected)
$7,225,000-9,211,000
The final EE/CA Alternative 2 is the recommended alternative. This alternative involves placing the tailings from the piles and ponds into an on-site repository near the tailings deposits. This represents a minor design change from the Draft Final EE/CA which conceptualized two repositories. Additional analyses demonstrated that a single repository is less expensive and reduces operation and maintenance requirements. The repository will be sited to keep the consolidated tailings out of the 500-year flood plain. The tailings that are contained near drainage courses will be relocated to reduce the potential for these tailings to be washed downstream during flood events. In addition, the channel will be restored and sized for the 500-year flood event, and run-on controls will be established around the repository. This alternative best met the screening criteria as most effective, implementable and cost-effective.
Requirements
High Clearance Vehicle
Location
40.298485° -112.166785° @ 5900'
From Fairfield, head south on Cedar Valley Rd/UT-73 toward 1620 N for 1.9 mi. Turn right at Manning Canyon Rd, and follow main road until you come upon the area.
