2002-03-04_REVISION - M1996076 - Laserfiche WebLink

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The property is within a larger area mapped by the Colorado Geological Survey as "A-2" on Plate 2 in the report "Mineral Resources Survey of Mesa County". The symbol A-2 is described as "alluvial fan, gravel, significant fines, decomposed or weak rock, and/or calcium carbonate". A drawing adapted from this Survey map is attached to this report. Western Slope Flagstone Quarry No. 2 Mr. Rudy Fontanari of Clifton, Colorado presently operates a quarry on his nearby property to produce primarily gravel, cobbles, and boulders in the southwest corner of Section 35, T 10 S, R 98 W, Sixth Principal Meridian. This quarry is about 0.5 mile east of the subject Powder Mountain Ranch property. The existing Western Slope F1agsLOne Quarry No. 2 operates under current permits for an area of 9.55 acres from the Colorado Mined Land Reclamation Board, Mesa County, and other authorities. The materials from the quarry have commercial value, after separation, for uses such as riprap, roadfill, landscaping stone, and other construction needs. Description of the Alluvial Fan Materials Based on exposures in nearby roadcuts and excavation at Quarry No. 2, the materials in the alluvial fans are generally an unsorted mixture of all sizes from silt and clay up to 10-foot boulders. The high fraction of very large rock sizes and the large amount of fines (silt and clay) indicate that the material was transported in a very high energy, debris-choked stream that could move giant boulders. The gradient of the present Rapid Creek is about 600 feet per mile, as the drainage descends from its head at 10,000-foot elevation on Grand Mesa down to its confluence with the Colorado River at about elevation 4,800 feet. The large volume of stream flow that would have been necessary to move such a volume of material is believed to have _ resulted from the melting of an ice cap on Grand Mesa in Pleistocene times. The debris-laden stream moved down the steep gradient of Rapid Creek and deposited its load as alluvial fans as the stream gradient lessened near the Colorado River. The fan materials in the exposures near the Powder Mountain Ranch property are estimated visually to be approximately 50 percent passing the No. 4 screen size (approximately < inch) and 50 percent that would be retained on a No. 4 screen. No samples have been screened to determine the exact gradings. The coarser fraction contains all sizes of gravel, cobbles, and boulders but seems to consist of a large amount of 6-inch to 36-inch rocks with some boulders up to 10 feet across. The rocks are almost entirely of hard, dense basalt which has originated from the lava capping on Grand Mesa, with a few sandstone clasts. The fragments range from angular to subrounded and are generally unweathered with varying amounts of vesicles 2