REV90451 - Laserfiche WebLink

Home Browse Search

Mining Plan METHODS OF MINING General Extraction Methods: Since Castle Concrete began mining, the most common method of mining its by benching. Although this procedure has contributed to the "corrugated" texture of the quanry site, the quarry could not be safely mined using any other method. This is primarily due to the steep slopes. For reclamation purposes, a bench is composed of two parts. First is the vertical backwall, and second is the more or less level portion that extends away from the hillside at the base of the backwall. The latter is referred to here as the step. Some people rei'er to the: step as the bench. Here, a bench is a combination of a step and a backwall. Drilling equipment and equipment used to remove the limestone after blasting needs fairly level ground for safe operation. Mining on steep slopes without benches can be very hazardous due to the possibilfity of sliding and the rock fall hazard. In the past, benches were created according to a maximum production approach. This resulted in benches that had a general configuration with about 30 foot backwalls and about 15 • foot steps. Some steps produced by this method were wider than 15 feet, but rarely exceeded 20 to 25 feet. The: backwalls though were very consistent. The steps produce a dividing line, • so to speak, between the walls. This combination of even height walls separated I>y steps produce the "corru.gated" texture. From a reclamation point of view, it is the configuration of the step that is important. Obviously, a wider step produces more room for revegetation, including trees that could eventually help reduce the "conugated" pattern created th part by the walls separated and defined by the steps. However, wider steps result in lost product and less than ideal resource recovery. Because the Mined Land Reclamation Act expects that mining and reclamation be done in a compatible manner; a compromise between maximum production and maximum reclamation potential needs to be found. Althoughu~ theory the way benches were produced in the past should have allowed for adequate revegetalion, the application of the theory did not have that result. Two problems occurred that blocked the path to implementing the kind of reclamation envisioned in the original permit. One problem was method of creating and preparing bench for reclamation. That will be corrected in all future mining. The other problem is a result of the geological structure of the deposit itself and may not be fully controllable. As will be discussed later, the only way this structural problem could have been avoided was to never dishrfi the site in the fast place. Unfortunately, by the time Castle Concrete arrived on the site the structural problem was already there and in operation in far more massive Page 10 Pikeview Quarry Amendment Exhibit D