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Logan Wash Mine TR No. 6 <br />The drainage pipe will consist of a 4-inch polyvinylchloride (PVC) Class 200 pipe with gasketed <br />joints that will extend from the existing 6-inch steel pipe in the Reseazch Mine vault to the north <br />end of the Lower Bench. At this point, approximately 250 feet of 4-inch high density <br />polyethylene (HDPE) rolled pipe will be installed along the steep, switch-backed alignment off <br />the bench to the location of the L-1 Portal discharge point in upper Dry Gulch, The rolled pipe <br />will adapt more easily to the bends in the 4-wheel drive track that forms the pipe alignment on <br />the north slope of the bench. <br />The existing Research Mine vault will be re-constructed to better accommodate access to the <br />mine drainage pipe for potential clean-out or by-pass purposes. The vault will be constructed <br />near the toe of the low-angled face of the Research Mine portal plug. The vault will consist of a <br />pre-fabricated concrete box or lazge diameter pipe with a manhole access cover. Within the <br />vault, the existing 6-inch steel discharge pipe will be fitted with a 6-inch flanged butterfly valve <br />and 4-inch T-fitting. The flanged fitting will allow dismantling of the pipe so that clean-out <br />work can be conducted. In addition, an emergency by-pass valve to a 6-inch discharge pipe will <br />be installed in the vault. The by-pass pipe will provide a location for sampling of the mine water <br />near the former portal and also an emergency discharge location in the event the 4-inch line were <br />to become blocked or restricted. The 6-inch by-pass pipe will extend out of the vault and <br />daylight at the toe of the portal plug. A blank flange will be installed on the end of the pipe. <br />The upper portion of the alignment will follow the Lower Bench access road to the Lower Bench <br />vault where the pipe can be accessed for clean-out or sampling purposes. Within the vault, a fl- <br />inch by 2-inch T-fitting will be installed with two valves, a flanged butterfly valve on the 4-inch <br />line and a gate valve on the 2-inch T-fitting. The purpose of the flange is to allow dismantling of <br />the pipe for clean-out purposes. The butterfly valve will allow shut-in of the mine drainage <br />water and sampling through the 2-inch T-fitting. The gate valve on the 2-inch T-fitting will <br />allow regulation of water while sampling. From the vault, the pipe alignment will continue <br />across the Lower Bench to the top of the north rim of the bench where transition to the rolled <br />HDPE pipe will occur. <br />Two air vent pipes will be installed in the pipe at evenly-spaced locations between the Research <br />Mine Bench and the Lower Bench. Each air vent fitting will consist of a 4-inch clean-out fitting. <br />The vent line will consist of 4-inch Schedule 40 PVC reduced to 2-inch Schedule 40 PVC with a <br />2-inch venting valve. The vent pipe will extend vertically to approximately 2 feet above ground <br />surface and be enclosed within a 6-inch steel pipe as protective casing. The steel pipe will have <br />a perforated lockable steel cap. <br />3.2 Pipe Sizing <br />Pipe sizing calculations were performed to (1) to estimate the flow rate in the case that a constant <br />head of 4-feet behind the concrete sack dam were to occur, and (2) estimate the pipe size <br />required to convey the maximum recorded daily flow rate, and flow rate associated with the <br />constant head calculation. The calculations are shown in Attachment C. <br />Western Water & Land, Inc. 6 <br />