1988-09-26_ENFORCEMENT - M1977378 (2)

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-8- "By comparison to data in Table D-4 on page D:5 of the 112 application for the Sunnyside Mine and Mill , Terry Tunnel pond muds show an increase in the silt/sand ratio over native Lake Emma sediments. Selective transport through the mine has resulted in a reduction in the sand content and increase in the silt content. Otherwise the materials are similar texturally. If these materials had been derived by precipitation from mine drainage water, the texture would have been clay with no silt or sand sized material present. The textural analysis alone confirms that these materials are lake sediments washed through the mine from Lake Emma, and that they are not sludges derived from the chemical treatment of the mine drainage waters. Extract results show that copper, lead, manganese and zinc concentrations are relatively high , but generally consistent with the Lake Emma Sediments in the Sunnyside Basin (Table D-2 , page D:4 112 application for the Sunnyside mine and Mill ). pH, conductivity, acid-base potential , and texture are all within reasonable bounds for plant growth media. Given these characteristics, it would be reasonable to attempt revegetating these materials. " The following documents the Division 's review of the Terry Tunnel sediment analysis , justifying the requirement to dispose the Terry Tunnel Sludge on the approved Tailing Pond Number 3 disposal site: a. The October 20, 1987 analysis relates the textural analysis of the Terry Tunnel ponds sediment to be: Sand: 16.5 - 28.4Z, Silt: 55.8 - 66.80% SiL Clay: 14.9 - 16.7c11V Table D-4 on page D:5 of the consolidated permit reia-es Lake Em,ia sediment textures as: Sand: OO-" S1It: 15 JCL/SL Clay: 20% and American Tunnel sludge textural analysis as: Sand: 61 Silt: 210% SL Clay: 18% The American Tunnel treated mine drainage precipitates (sludge) more closely relate to the Lake Emma sediments than do the Terry Tunnel Pond sediment analysis. Sand and silt components of the American Tunnel sludge comprise 82% of the particle sizes evaluated.