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1. The lower part of the glacial till and terrace deposits on-site is a relatively thin <br /> layer of sand, most likely river deposited, that is not likely to be continuous <br /> throughout the area and can be (on a larger scale) considered part of the <br /> alluvium. <br /> 2. There are lenses of cohesive soil (clay) in the till, varying but more common near <br /> the top of the profile. <br /> 11. The sand is located above the Lewis shale (with an intermediate zone of mixed but <br /> unlayered materials 5-10 feet in thickness), into which the Animas River has carved <br /> much of its valley. This shale is the foundation and floor of the pit, and is not mined. <br /> Unlike areas to the south and east (Carbon Junction Canyon), the shale, though <br /> dipping to the South-southeast at about 200, is not coal-bearing or a source of <br /> coalbed methane.3 Observation of shale exposed in mining establishes that the shale <br /> is competent with no indications of weathering. <br /> 12. The entire profile of the pit is above the water table. There are no known springs or <br /> seeps on the site or in the vicinity. <br /> The J&J Pit is one of a series of sand and gravel operations along the west slope of Ewing <br /> Mesa stretching from Section 33 of T34R09 to the north, to the Carbon Junction Canyon <br /> which separates Ewing Mesa from Grandview Mesa to the east, where additional operations <br /> (Montoya Pit and Crader Pit) are mining in these same formations. Older, long-closed <br /> aggregate mining has been done on the west side of Animas River Valley, from north of US- <br /> 160 to opposite Farmington Hill. All these locations provide insight to the type of setting of the <br /> material being mined and exposed at the J&J Pit. <br /> Discussion of each item: <br /> 9) There is no evidence of any geological hazards which provide any significant potential <br /> threat to any operations or structures now in or proposed within the affected areas. <br /> Nor are there any geologic hazards (within or in the vicinity of the affected lands) that <br /> past or proposed mining or reclamation activities would de-stabilize or make worse <br /> (exacerbate). This is based on observations by the preparer of this report, personnel of <br /> DRMS, the engineer for CrossFire Aggregates Products and others, research on <br /> geology, soils, and hazards in county, state, and federal records, and other sources. <br /> Erosion hazards noted by La Plata County are of the surficial loess-derived soils. <br /> 10) Engineering stability analyses: <br /> 1) No wastepiles or embankments are proposed during mining and reclamation, <br /> except for existing scrap/salvage piles of materials (metals, tires, soil) limited to <br /> maximum 20 feet height and intended to be temporary as materials are received, <br /> processed, and shipped off-site. All wastepiles and stockpiles at the head of any <br /> highwall or working face shall have the toe a minimum of 10 feet back from any <br /> highwall greater than 20 feet high, during mining operations. <br /> 2) Based on the proposed method of mining (see Exhibit B), the slopes configuration <br /> as may occur during operations include no embankments but do include highwalls <br /> 3 The Carbon Junction Canyon exposes the Fruitland Formation which is/has been mined for coal and <br /> other minerals, and is a source of coal-bed methane. Conditions to the SW of Carbon Junction Canyon are very <br /> similar to this site. <br /> Technical Revision to M1985-001 J&J Pit, LaPlata County, dated 24 AUG 2016 Page 25 <br />