Dames & Moore, 1999 - USDA Forest Service

3.5.2 Asbestos Assessment
The partially salvaged mill building contains materials which are exposed and suspected to consist of
asbestos-containing materials. Three samples of the materials (AM 1 through AM3) were collected from
the mill structure. The samples were representative of both wall insulation materials and a coating on the
insulation. The sampling was conducted in general accordance with AHERA standards. The number of
samples was agreed upon by the Holden Mine RIIFS Technical Advisory Group to be sufficient for RI
characterization. The results of the laboratory analyses are presented in Section 5.8.
3.6 TASK 6 - MINE ASSESSMENT
Referring to Figure 3.0-3, the underground mine is situated south to southwest of the former mill building
in the area noted as Honeymoon Heights. Access to the underground mine was provided by eight portals.
Mine waste rock piles were generated during mine development; each of the piles is situated near the
mine portals. The aboveground and belowground elements of the mine were evaluated as part of the RI.
3.6.1 Review of Aboveground and Underground Mine Maps
Relatively detailed mine maps were developed during the operation of the mine and after the mine was
closed. The maps were reviewed to evaluate the presence and, extent of internal workings of the mine and
the potential pathways for groundwater migration, and to assess the options and safety considerations for
possible mine portal entry during the RI field program. The maps were also reviewed by both a mining
engineer and a miner who were subcontracted by Dames & Moore. The results of the assessment are
discussed in Section 4.1.3.1.
3.6.2 Field Assessment of Aboveground Features
3.6.2.1 Evaluation of Mine Openings and Related Features
Inventory of Aboveground Features
The primary aboveground features associated with the historic mining at the 1500-level of the mine and in
the Honeymoon Heighis were inventoried in the field. The inventory focused on the portal openings and
mine rock piles associated with the openings. The locations of the 1500-level openings were located by
civil survey. The portals in the Honeymoon Heights area were located utilizing Global Positioning
System (GPS) methods and aerial photographs of the Site: The results of the inventory are presented in
Section 4.1.2.8.
The ore body mined by Howe Sound and others is nearly vertical in orientation and is exposed at the
ground surface in the Honeymoon Heights area. Portions of the ore body were removed during the earlier
years (1938 to 1945) of underground mining. The surface expression of the ore body is evident in the
field. A reconnaissance of the area where the ore body is exposed at the ground surface was completed in
order to document areas where subsidence may have occurred and the potential for future subsidence. A
discussion of the methods employed to evaluate the mine subsidence potential was presented in Section
3.1.5. A discussion of the field findings is presented in Section 4.2.5.
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17693405419Uuly 19, 1999:2:07 PM;DRAFI' FINAL RI REPORT