From a public health assessment report.
The Elizabeth Mine site is located in the towns of Strafford and Thetford in east-central Vermont, approximately 1.9 miles southeast of the village of South Strafford, on the eastern flank of Copperas Hill. The site is approximately 15 miles north of White River Junction, and 9 miles west of the Connecticut River (Appendix A, Figure 1) (EPA 2002). Old Mine Road runs to the northwest from the northern tip of the Elizabeth Mine site. Three families live on Old Mine Road, a dirt road located adjacent to and to the west of the site. The closest home is 150 feet from the northern boundary of the Elizabeth Mine site.
The site contains open pit mines (two open cuts), extensive underground workings (mine shafts and adits), three tailings areas, several buildings, and a satellite area (South Mine) with tailings and a shaft. Underground mines drain to surface water through the Air Vent, a 1-foot diameter iron pipe located south of the Ompompanoosuc River. Tailings Pile 1 (TP1, 30 acres) and Tailings Pile 2 (TP2, 2 acres) are located in the northeastern portion of the site. The tailings piles consist of fine-grained tailings from a flotation mill that operated on-site from 1943 to 1958 (USGS 2000). A local landowner previously covered parts of TP1 with 6 inches of topsoil in order to grow vegetation and reduce wind-blown dust. Some trees and sparse vegetation grew in those areas. Tailings Pile 3 (TP3, 6 acres), located in the southwestern corner of the site, consists of coarser mine spoils from earlier mining operations (USGS 2000); it has little vegetation except for a few small birch and white pine trees. All three tailings piles are within 0.5 mile of the nearest residences.
Most of the immediate area is barren, but dense trees grow nearby. Multiple small streams, some very wide and some very narrow, run through the site, along mine cuts or alongside steep hills of tailings piles. Copperas and Lords Brooks pass through the site and flow into the West Branch of the Ompompanoosuc River (WBOR) north of the site. Access to some portions of the site is restricted by a fence. An unpaved dirt road cuts across another portion of the site (TP3). The site is private property and the land owner has posted private property signs; however, EPA has not posted any additional signs. EPA has documented that loggers and recreational users (such as all-terrain vehicle riders) use the unpaved road (EPA 2003b).
Elizabeth Mine opened in 1793 when a large sulfide ore deposit was discovered southeast of South Strafford. Pyrrhotite (iron ore and iron sulfate) was mined to produce copperas. Copperas is used for sulfuric acid production, as a disinfectant and sheep dip, as an astringent medicine, as a drier in the manufacturing of ground pigment, and as blackening and coloring for leather. Large scale production of copperas began in 1810 and continued until the 1880s. Copper mining began in 1830, when the Strafford Copper Works was formed. Copper mining continued until 1930, when the mine closed temporarily. The mine remained closed until 1942, when it reopened to provide copper for World War II use. Most of the underground copper mining at the Elizabeth Mine site took place between 1942 and 1958, when the mine was closed permanently (EPA 2002).
Investigations to identify if the Elizabeth Mine site was a source of pollution to the West Branch of the Ompompanoosuc River (WBOR_ began in the 1970s. In 1999, the Vermont Department of Environmental Conservation (VTDEC) requested that the U.S. Environmental Protection Agency (EPA) assist in conducting additional assessments of the site (EPA 2002). In 2000, VTDEC and EPA conducted investigations and collected samples at the site. VTDEC and EPA collected drinking water, surface soil, air, and indoor dust and wipe samples from residential homes near the site on Old Mine Road. The U.S. Geological Survey (USGS) collected composite waste dump and tailings soil samples from the site. EPA collected surface water, sediment, and fish tissue samples in 2000 and 2001.
On the basis of the data obtained from analyzing the samples, EPA proposed a phased cleanup for the Elizabeth Mine site, that included early cleanup of the most obvious sources of contamination, followed by cleanup of remaining areas of contamination as identified by a planned remedial investigation and feasibility study (RI/FS). EPA began the RI/FS in 2000 and anticipates completion in 2003, depending on available funding. Additional groundwater sampling is proposed as part of the RI/FS (EPA 2003a). The RI/FS is intended to determine the need and scope of any additional cleanup actions. The early cleanup plan consists of diverting clean surface water and groundwater flow around the tailings piles, capturing and treating acid mine drainage flowing from one tailings pile and from the toe of another tailings pile using a combination of natural treatment systems, to preserve a portion (up to 100%) of the copper waste rock and copperas heap leaching piles adjacent to the North Open Cut, and covering two tailings piles with a cover system to limit infiltration (EPA 2002). Appendix C details the operational and regulatory history of the Elizabeth Mine site.