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-12- IV. Geolo,y - Rules 2.0.1.5 and 2.04,6 Geology information is contained in VoZ ura° I, Chapter Zv, page 10-22 and Volume IV, page Z48-170 of the Trinidad Basin hfining application. Mining will extract the DeZ Agua and Cass coal seams of the Raton Formation. These units are the two uppermost seams of this formation. An interval of strata 80 to 100 feet thick separates the two seams. This interval consists of a series of sandstones, siltstones, and shales which vary locally in expression within the permit area. Overburden samples were obtained from several core holes, as well as from highwall samples. These samples were analyzed according to Division guidelines for over- burden geochemistry data collection. The results of this analysis indicates that overall, the overburden does not pose any acid-forming, toxic-forming or alkalinity-forming characteristics that would inhibit reclamation or degrade water resources. Only one unit was found to have geochemical characteristics near or above suspect levels. This unit is a shale that appears SZ feet below the Del Agua seam and is less than two feet in thickness. [/it}un this unit a 1-2 inch coal lens can be identified which is sodic and high in sulfates. This shale unit makes up less than 3e of the total overburden volume to be removed and, therefore, wZ11 not significantly affect overall spoil quality. Thi- :nit will be replaced within the backfilled spoil so as to minimize any chance of exposure to the surface which might affect reclamation efforts. The information contained in the application satisfies the requirements of this section. V. Hydrologic Balance: Surface Water - Rules 2,04.5, 2.04.7, 2.05.3(4), 2.05,6(3) and 4.05 Information regarding surface water characteristics is located in Volume I, chapter IV, pages 13, I4, 23-4Z; Volume III, Section 2.04.7; and Volume V - Report on Hydrologic Impacts - in the permit application. The Division has reviewed this information with respect to compliance with the Rules and Regulations. Mining will occur on the north and south slopes adjacent to Del Agua Canyon. This drainage is tributary to the Arkansas River and is ephemeral in the upper reaches to intermittant in the lower reaches of the stream. No other significant streams exist within the mine permit or adjacent area. The Del Agua Canyon drainage adjacent to the mine is ephemeral and flows only in response to snowmelt or rainfall events. Hydrologic monitoring of surface water over the past three years has only identified a few isolated runoff events. On two occasions, no Flow was identified on the upstream gage, whereas a small low flow was identified at the downstream site. This may be due to a shallower depth to ground water table of the lower site, or from an increase in runoff from the mine area. No abnormal erosional features have been identified in the stream that would support the latter.