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13 <br />• <br /> <br />• <br />Overburden <br />Forty-one samples of individual overburden strata and <br />3 composite samples from 3 core holes were analyzed for <br />physical and chemical properties important to reclamation <br />(appendix C). The typical Laramie formation overburden <br />on the proposed mine site is described as follows: <br />pH, 7.6 Within the pH range expected <br />for calcareous material - this <br />pH should not pose a problem <br />for native species to be used <br />in revegetation. <br />Soluble salts Somewhat salty - unsuitable for <br />4-6 mmhos/cm surface soil but should be okay <br />as a soil material acting as a <br />deep reservoir to hold plant- <br />available water. <br />Sodium Adsorption Ratio This much sodium will limit the <br />10-16 rate of water movement into and <br />through this clayey material if <br />soluble salts are leached out. <br />Plant Available Nutrients N and P very deficient - others <br />adequate. <br />Texture, clay Unsuitable as surface soil <br />._ material, if placed beneath <br />sand should be acceptable <br />because of its large water <br />holding capacity. <br />Possible Toxic Ions <br />Analysis for plant-available <br />selenium show low or moderate <br />concentrations by the 4-hour <br />hot-water extraction method. <br />Plant-available molybdenum is <br />low to moderate in most of the <br />samples. Two of the samples <br />tested high in Mo in relation <br />to the other samples by the <br />(NH ) CO3 test for plant-avail- <br />abl~ ~fo, both of these samples <br />were dark gray carbonaceous <br />shales. One sample tested very <br />high in B (>9 ppm B, 5-minute <br /> <br />