A10_AttachD.3_ExampleScenario2.docx

Solicitation Number: 12970223R0014 Region 5 CERCLA Environmental Response IDIQ Page 1 of 7 Special Projects Operation Center – Southwest Region Contractor(s) TBD

Attachment D.3 Example Scenario 2 – Potentially Responsible Party Investigation

For the scenario provided below, prepare, and submit:

· A conceptual Potentially Responsible Party (PRP) Search work plan that provides a description of how contractor would address the scenario. The work plan needs to include and address the following:

· Description of the work to be performed, including site background investigation methodology, record collection, title search.

· Discussion of any specific exclusions/assumptions the contractor may have regarding their response to the scenario in question.

· Conceptual listing of personnel, including subcontractor(s) that would be utilized for the response.

· Price Proposal to accompany the conceptual PRP Search Workplan

· Example of a previous PRP Search Report that the firm has prepared (can be redacted as necessary.

SITE SCENARIO:

The contractor shall conduct a conducting a Potentially Responsible Party Search under Activity VI, Task 1 of Section III of the Regional CERCLA Environmental Response Contract.

Site Description:

The Williams Brothers mine is located within the Sierra Nevada about three-quarters of a mile south-southeast of Browns Peak within the South Fork of the Merced River drainage. It is represented on the El Portal 7.5-minute topographic quadrangle. Site elevation is approximately 4360 feet ASL (above sea level). The mine is wholly on National Forest System land and is administered by the Bass Lake Ranger District, Sierra National Forest.

The site is located approximately 30 miles northeast of Mariposa, California (Fig. 1). It is found in the southwest 1/4 of Section 32, Township 3 South, Range 30 East. This location is within Mariposa County. Williams Brothers mine is at approximately 37.627 degrees North latitude and 119.795 degrees West longitude.

The site is reached by taking California State Highway 140 to the access road junction near El Portal, California. While the straight line distance from the road junction is 2.5 miles, the winding 9-mile dirt road with 48 switchback turns leading from Highway 140 in Merced Canyon to the ridge near Canty Meadow (Fig. 2). The ridge is a divide between the Merced River and the South Fork of the Merced River. The road continues several miles farther down the other side of the ridge to the site.

Operational Setting and History:

The Site is a historic gold mine with an associated ore processing area. The Site has also been referred to in literature and records as the Gibbs Mine and Sally-Anne Project. The name Gibbs mine pre-dates the name Williams Brothers and the Sally-Anne name post-dates it. In recent time, it was operated by AT&E Enterprises and USA Mining. The Williams Brothers mine is one of eleven mines listed for the Hite Cove Gold Mining District. Records indicate that the Gibbs Mine operations and development the 1860s contemporaneous with the time of discovery at the nearby Hite mine and the adjacent Mexican or El Carmen mine. Literature indicates that the development of the Site’s 3 drift adits took place during this time. The Site was acquired by the Williams Brothers sometime in the 1940s. Forest Service minerals reports indicate that the mine was sold to AT&E enterprises in 1982 and that limited mining occurred at the Site up until 1998. When the Site was placed in court receivership under USA Mining. In 2006, the mining claims lapsed, and the site is abandoned.

Deliverables:

Format and Contents of work plans and reports shall be in accordance Potentially Responsible Party Investigation, Activity VI, Task 1 of Section III of the Regional CERCLA Environmental Response Contract.

Figure 1 Location map for the Williams Brothers Mine site. The red star denotes the site location.

Figure 2. Part of the El Portal 7.5-minute topographic map showing the site of the Williams Brothers mine and surrounding area. Note the multiple switchback road leading from California Highway 140 (to the north of the mine site) south to Canty Meadow and the site.

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