Laserfiche WebLink
<br />available mass of pyrite is exhausted. Williams and Clark calculate that for spoil containing <br />1.090 pyrite (by weight) it takes 1,600 years to oxidize all of the pyrite (their Table 18). <br />Like the Seneca II Mine, the dominant anion in spoil aquifer water at New Horizon would <br />probably be sulfate; therefore, the oxidation of pyrite will be the main source of increased TDS <br />in spoil aquifer water a[ New Horizon. The pyritic sulfur content in New Horizon's spoil can <br />be expected to be similar to the 0.~79o at the Hamilton Iviine. seven miles away. because both <br />mines are developed in the same stratigraphic units. Pyrite is ~39o sulfur (by weight): therefore, <br />the 0.5790 pyritic sulfur content indicates that pyrite comprises roughly 0.8490 of the mass of <br />New Horizon's spoil. Applying Williams and Clark's 1,600-year exhaustion time far 1.090 <br />pyrite, New Horizon's spoil can be expected to generate hieh sulfate concentrations for at least <br />1.000 years. <br />8. Page 2.04.7-47, section titled "Impact of spoil water quality....". Please add your projection of sulfate and <br />TDS concentrations in spoil aquifer water. <br />9. Page 2.04.7-4, second paragraph, first sentence. Please edit this sentence to clarify the meaning of "general <br />downward vertical head". <br />10. Page 2.04.7-22, section titled "Drainage basin geomorphology....". Please revise this section, if necessary, <br />to reflect any of the mine's drainage to Tuttle Draw. <br />I I. Page 2.04.7-9, second paragraph, last sentence. Lysime[er studies of spoil aquifers at the Seneca II Mine in <br />Rout[ County (USGS Water-Resources Investigations Report 92-4187, 1994) suggested annual infiltration <br />from precipitation there was 3 inches per year. By analogy, annual infiltration from precipitation at New <br />Horizon probably is at least two inches per year. Is two inches only a very minor component of New <br />Horizon's total infiltration'? How many inches do you believe occurs from irrigation at New Horizon? <br />12. Page 2.04.7-9, second paragraph, fifth sentence, begins "Using the described....". Please revise this sentence <br />to be consistent with the increase in spoil permeability that is predicted on page 2.05.6(3)(b)(v)-2, second <br />paragraph. <br />l3. Page 2.05.6(3)-12, first complete sentence, begins "No principal irrigation....". Please revise this sentence to <br />reflect West Lateral ditch's crossing the permit area. <br />Page 16-6, last sentence of fourth paragraph. This sentence refers to a water rights plan in Attachment 16-I. <br />This Attachment cannot be found in the Division's copies of the permit application. Please provide two copies <br />~~ o;Attaghment 16-I. <br />V ~`~„~\/\~` <br />SOILS & REVEGETATION SECTION <br />2.04.9 Soils Resource Information <br />Soil map units identified in the 1998 study area are different than those identified in the 1988 and 1996 study <br />areas, immediately adjacent. This may be due to recent revision of the MRCS soil survey for the area, but <br />some explanation should be provided in the application narrative. <br />2. Page 2.04.9-10, narrative indicates that salvage depths for each map unit are weighted averages of each major <br />component of the map unit, which would be appropriate. Table 2.04.9-3 lists sample sites within each map <br />unit, but does not specify the major component (soil series) represented by the sample, nor does it indicate the <br />percentage of the map unit represented by each major component. This information should be provided. <br />