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AmClrX T Ct) <br />Geology & Depositional Model <br />2) Geologic Modeling <br />Part of the task of evaluating the underground potential of the NKC/NEDO project area is the <br />development of a geological interpretation (depositional model) that can relate the historical <br />sequence which resulted in the accumulation of the coal beds and associated strata. The principle <br />value of the model is that it can become a predictive tool to determine areas where coal beds thin <br />or split, areas of potentially dangerous roof conditions and coal quality. While this report'will <br />not be a detailed depositional model since the older drill hole data was not available with <br />complete lithologic interpretation (in order to compete detailed coal parting and interburden <br />isopachs), I will discuss the more easily defined trends present. <br />Perhaps the most important factor influencing local distribution of the thicker coal is the <br />character of the surface upon which the plant material accumulated. Geologists often refer to <br />such a surface as the paleotopography, paleodrainage or depositional platform. The shape and <br />extent of a depositional platform is often controlled by the varying thickness of the sediments <br />below. The sediments below the platform are often controlled by various rates of compaction. <br />Thicker trends in a lower coal seam or shale bed are often subjected to higher rates of <br />compaction, therefore, they form paleotopographic lows that can influence or attract drainage <br />patterns (i.e. sand channel systems resulting in sediment accumulation) in the coal forming <br />environment. Conversely, the previous (now buried) channel would be composed of less <br />compactable lithologies (sandstone to siltstone) forming a paleotopographic high, which would <br />allow for the growth and accumulation of peat. <br />Mapping each vertical sequence of coal/sediment accumulation represents a fall cycle of <br />deposition. Observing the lateral changes within each depositional sequence and interrelating <br />(overlaying) this information can help define the extent of the thicker coal, parting trends, quality <br />variations within a given area and to some extent the sand channel trends overlying a mine roof. <br />Additionally, the observation of depositional trends, such as sand channels or seam splits, can <br />indicate local and regional structural features. Variations in the thickness (and/or stacking), <br />width, or lateral direction of seam splits or sand channels may represent basinal compaction <br />during coal formation and/or older pre -depositional tectonic activity. Not only would these <br />features influence the accumulation of the peat but may represent zones affecting the minability <br />of the coal by inclusion of lineaments, shears/slips, and/or faults. <br />When the data is observed as an interrelated sequence of events, the best interpretation can be <br />surmised. The geologic model provides a baseline of information that can be added to, changed <br />or even completely revised as additional data is obtained. It allows the geologist to provide mine <br />personnel with the best critical mine planning/operational information available, and also can <br />assist in locating sites where additional information would be useful, with less expense and <br />wasted time. Finally, the model is invaluable in targeting additional areas for reserve acquisition <br />or exploration. <br />