Laserfiche WebLink
• ATTACHDIENT 6 <br />weathered layers with high ESP values and high clay contents, but some benefits <br />in properties can be gained by mixing with adjacent sandstone layers as indi- <br />cated previously. <br />In the East and West Panels, 48 layers of coal occur in the 11 holes. <br />Immediately above these coal seams, the major layer is sandstone in 13 cases, <br />shale plus silts tone in 25 cases, and shale in 10 cases. Shale fragments <br />weather rapidly, some in less than one year, so these particles offer the <br />least protection against erosion. Siltstone fragments weather a[ intermediate <br />rates between shale and sandstone, but probably at a rate closer to shale. <br />3.24 Available K, Fe and Zn <br />These plant nutrients are not likely to be limiting factors for plant <br />growth in the overburden from either panel. The lower values for available <br />K are associated vith sandstone layers, but adjacent shale layers contain <br />ample supplies of K. <br />3.25 Available P <br />All of the overburden is deficient in ayailable P, with two minor <br />exceptions in hole CR 216. When the available P level is less than 12 ppm, <br />a response to added fertilizer P may be expected. The overburden in hole <br />• CR 219 shows extremely low values of available P. <br />3.26 Organic matter <br />These values vary considerably in the overburden probably due partly to <br />an influence of carbon from impure coal. Very low values are associated with <br />sandstone layers. The shale layers tend to be quite high in organic matter. <br />In layers of shale also high in ESP values, the high organic matter will likely <br />help stabilize these layers as weathering proceeds. <br />3.27 Available N as nitrate <br />Some layers of [he overburden contain levels of N that could be nearly <br />adequate for plants, but the contribution of N by mineralization of the organic <br />matter in these layers is unknown. Mast of the overburden is deficient in <br />available N and responses to fertilizer N would be expected generally. In <br />other states (N, Dakota) overburden contains exchangeable ammonium N which be- <br />comes available to plants as weathering proceeds. Such measurements were not <br />made for the overburden under consideration. <br />4. Results of artificial weathering of selected samples <br />The objective in this study of 21 samples was to enhance the rate of <br />weathering artificially by 40 freeze-thaw cycles. Changes induced by this <br />kind of weathering would indicate some of the expected changes likely to occur <br />naturally and [he data would assist in diagnosing the properties of the over- <br />. burden. Changes in particle size distribution and chemical properties were <br />measured as affected by weathering. In addition the water content at one-third <br />and 15 bars suction was measured. A physical test of the settling volume was <br />measured. This measurement should be useful as a field test to indicate over- <br />burden materials with high ESP values and high clay content. Observations on <br />14 <br />