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<br /> <br />are inferior to the river gravels from either a quality or a <br />cost standpoint. The river gravels vary from almost no useable <br />gravel to depths of over twenty feet with the preponderance <br />of gravel depths being twelve feet or less. <br />The cost of transporting gravel 10 miles is approximately equal <br />to all costs of processing, nearly doubling the cost of gravel <br />to the customer. Close-in graveling of high quality gravel <br />deposits is therefore much more economical for the processor <br />and the customer. <br />Ma7-h nri <br />Sand and gravel mining operations across the country vary <br />widely in the methods used for extraction. This is due to <br />topography of the site, depth and thickness of the gravel <br />deposit, height of the water table, quantity and rate of <br />material extraction and equipment availability, and other <br />considerations. <br />Most Flatiron mining operations are open pit excavations. The <br />procedures and equipment used are as follows: <br />1. Scrapers are used to remove the topsoil and to expose the <br />aggregate below. <br />2. Because the aggregate is mined dry, a backhoe is used at <br />this stage. The backhoe will dig a dewatering trench around <br />the area to be mined. <br />D-2 <br />