The Site is located in the Wurtsboro Ridge State Forest in the Town of Mamakating, Sullivan County, New York and the Delaware and Hudson (D&H) Canal Linear Park. The area of contamination associated with the mine operation encompasses approximately 20-acres of the 1,000-acre State Forest.
The Site is comprised of two main areas: the upper area of former mining operations and the lower area of former ore processing operations. The elevation between upper and lower portions range from approximately 1300-feet above mean sea level (msl) to 550-feet above msl. The upper portion is owned by the State of New York and managed by NYSDEC. The lower portion is primarily located on state-owned land, however contamination extends to the adjacent Delaware and Hudson (D&H) Canal Linear Park, which is owned and maintained by Sullivan County.
The mine was historically known as the Shawangunk Mine and the Mamakating Mine, which was one of several zinc-lead mines in the Shawangunk Mountains. During mining operations, low-grade overburden was extracted from shafts to reach veins of high-grade galena. The galena ore was conveyed via an aerial tram, which carried the material down the slope to the mill. The mining operation created four distinct surface deposits of mine tailings that remain on the property. Three of the tailing deposits are located in the upper area adjacent to the old mine shafts. The fourth is comprised of sand sized material resulting from the milling process, which is located in the lower area adjacent to the D&H Canal and Linear Park. Groundwater discharge, which emanates from the upper mine and lower mine runs through the tailing piles and discharges into the D&H Canal. Soil particles from the lower tailings pile have migrated and accumulated as a fine-grained sediment deposit in the D&H Canal.
The NYSDEC posted warning signs around the perimeters of the tailings piles, establishing restricted areas warning the public that the soil and water in the area is contaminated with lead.
The principal threat to the public is direct contact with high levels of lead in the tailings piles and surface/ground water runoff. The tailings piles have been tested and found to contain Toxicity Characteristic Leaching Procedure (TCLP) concentrations ranging from 5.3 to 268 parts per million (ppm). A TCLP concentration of 5ppm meets the regulatory criteria as a hazardous waste. Water samples collected at the lower mine discharge point have been found to contain lead concentrations which range from 410 to 710 parts per billion (ppb). The NYSDEC ecological Quality Standard for lead in surface water is 4.1ppb.
The site is accessed by the public as evidenced by all-terrain vehicle tracks, empty beverage containers, signs of target shooting, the presence of a geocache, and websites describing the collection of galena fragments in the tailings piles. The public would be exposed to hazardous substances during their visits to the area. NYSDEC requested that the EPA consider an emergency removal action to address the direct contact threat to hazardous substances, particularly lead.
Prior to initiating any action at a mine site, EPA Headquarters approval is now required. Headquarters provided written authorization to Region 2’s Removal Action Branch on September 17, 2015.
On September 22 and 23, 2015, EPA met with NYSDEC representatives at the Site to inspect the upper and lower former operation areas.
Based on the NYSDEC sampling events and results from their laboratory analysis, the mine tailings, millings, overburden rock and surface water are considered CERCLA designated hazardous substances as defined in section 101(14) of CERCLA, 42 U.S.C. § 9601(14). The Site is defined as a facility under section 101(9) of CERCLA, 42 U.S.C. § 9601(9). Conditions at the Site meet the requirements of Section 300.415(b) of the National Contingency Plan (NCP) for the undertaking of a CERCLA removal action.
The Removal Action activities to be conducted under this verbal authorization will include:
: Consolidating wastes;
: Installing security fencing and signage;
: Evaluation/Stabilization of entrance roads;
: Pre-classification of wastes;
: Preparation of work plans to remove lead-contaminated wastes; and
: Pilot tests on passive treatment systems for surface water discharges.
