Laserfiche WebLink
Where a tunnel or adit intersects a vein or fault, it functions as a horizontal well and any flow <br />along the fracture or vein enters the tunnel or adit and then flows out of the portal. The <br />generally low to non - existent flow from the adits /tunnels which based on Eckells block <br />model intersect almost all of the fractures and veins supports the theory of low recharge <br />locally. <br />There is water produced at the Idaho No. 1 Mine Portal probably due to recharge of the <br />Entrada Formation which is the surficial geologic unit in the immediate vicinity of the portal <br />and which is generally more permeable particularly vertically then most of the other <br />formations in the area. The recharged groundwater travels along the Entrada - Dolores <br />formation contact until it is intersected by the Idaho Fault and then the Idaho No. 1 tunnel. <br />6.0 RECOMMENDATIONS <br />To refine this model particularly in the vicinity of the Idaho No. 1 tunnel, a water budget <br />should be developed that concentrates on lag time from runoff events to production. To <br />accomplish this, a recording flow meter should be placed in the discharge from the tunnel. A <br />recording rain gauge should be placed in the immediate vicinity to allow correlation between <br />water production and recharge events. Finally, snow pack and water content measurements <br />should be made during winter months in the local recharge area to allow the addition of this <br />source into the water budget. <br />A program should be initiated to analyze the discharge from the Idaho No. 1 discharge for <br />common ions or indicators to evaluate if changes in water chemistry can be related to the <br />changes in runoff characteristics. In addition, sampling points should be established at the <br />discharge of both the May Day No 1 tunnel and along the May Day No. 2 bench. In addition, <br />if there is produced water deeper in the May Day No. 1 tunnel, samples should be collected <br />for common ion analyses and geochemical characterization performed in an effort to <br />establish source rock geochemistry for the water. This then can be used as in developing <br />potential transport or lack of transport scenarios for movement of water through the mine <br />areas. <br />At this time under this conceptual model, there are no recommended locations for installation <br />of monitoring wells that would be completed to the approximate elevation of the 8790 ft <br />AMSL level in the vicinity of the Idaho No. 1 or May Day No. 1 portals or in the <br />intermediate areas. The general lack of water production from the tunnels, the small recharge <br />area of the units above this elevation and the observations on site suggest that there are no <br />extensive saturated zones in this area. Instead, it would be more prudent financially to: <br />1. Collect surface water samples in the Little Deadwood Gulch drainage, the La Plata <br />River drainage and from seeps within the mine tunnels. These should be analyzed for <br />a complete suite of anions and cations and compared. If these samples are <br />geochemically equivalent, then the primary source of discharge from the tunnels is <br />surface recharge probably moving relatively rapidly through fractures. <br />2. Survey lower levels of the May Day No. 1 for flooding and increased water <br />production. Where seeps are found, perform the geochemical analyses suggested in <br />