The Big River Mine - Lake Timberline Area is an on-going time-critical removal action at the Central Middle School Sub-Site (Site) and consists of high concentrations of lead contamination from mining and the use of mine waste as construction materials. The primary problem areas at this Site, which require action, are lead-contaminated soils in yards and gravel in driveways. 

The Site is located in northern St. Francois County and is a stand-alone lake development community north of the city of Bonne Terre and south of Valle Mines, Missouri. 

1.1.2.2 Description of Threat

According to the Incidents of Mines, Occurrences and Prospects (IMOP) database created by the state of Missouri, there was only limited mining within the current boundaries of Lake Timberline. However, the Mississippi River and Bonne Terre Railway (MR&BTR) runs through the development. This railway (now abandoned) is comprised of mine waste (chat, tailings, smelter slag, etc.) based on visual observations and sample results. Three lakes within the development are adjacent to and receive storm-water runoff from the MR&BTR. In addition, based on documented conversations with some Lake Timberline residents, it appears lead-contaminated soil and gravel has been brought in from the surrounding areas. The soil was used as fill and the gravel was used for driveways throughout the community. 

Elevated concentrations, greater than 400 parts per million (ppm), of lead have been found throughout the Site. Children playing in and around the contaminated areas have the highest potential to be exposed. 

1.1.3 Preliminary Removal Assessment/Removal Site Inspection Results

In September 2005, the U.S. Environmental Protection Agency conducted screening of a portion of the MR&BTR, which runs through the development along with soil from a nearby playground and sediment from Kiddie Lake.  The screening was conducted with an X-Ray Florescence Spectrometer (XRF) and the results detected lead contamination in the pond sediments at levels ranging from 1,383 to 2,793 ppm, results from soil screened in the park ranged from 213 to 3,390 ppm, and results from screening of the abandoned railroad ballast ranged from 646 to 2,080 ppm. 

In March 2010, the EPA began a removal assessment which included soil and groundwater sampling in the Lake Timberline area. During this sampling event, the EPA contractors screened the soil at 362 residences and sampled 226 private drinking water wells. The results of this sampling effort revealed the following information:

Properties with Soil Levels greater than 400 ppm lead………….……209

Properties with Soil Levels greater than 1,200 ppm lead …..  ………104

Drinking Water Wells Exceeding 15 parts per billion lead…… ….. None

* The above accounting of expenditures is an estimate based on figures known to the OSC at the time this report was written. The OSC does not necessarily receive specific figures on final payments made to any contractor(s). Other financial data which the OSC must rely upon may not be entirely up-to-date. The cost accounting provided in this report does not necessarily represent an exact monetary figure which the government may include in any claim for cost recovery.