Laserfiche WebLink
25 <br />PHYSICAL FACTORS AFFECTING DRAINAGE QUALITY <br />• <br />This chapter discusses how other geologic and hydrologic <br />factors will change the weathering reactions of the ore <br />minerals. Investigations within the Front Range of Colorado <br />have shown that at least three other parameters are important <br />for determining the chemistry of a drainage. These are the <br />ore petrology, the ground water hydrology and the physical <br />occurrence of the ore in the ground. Each of these will <br />be discussed. Much of what follows also occurs in two other <br />papers (11, 12). <br />ORE PETROLOGY VS. WATER QUALITY <br />In the Central City Mining District, the zones of minera- <br />lization have.been well established (4). These zones are <br />• shown in figure 2; and figure 3 shows the zonal distribution <br />of the vein forming minerals. The central zone consists <br />of pyrite veins and it is surrounded by a peripheral zone of <br />galena-sphalerite veins. The intermediate zone, which con- <br />tains most of the important mines, has transitional veins <br />that consist of minerals characteristic of the other two <br />zones. Wildeman and others (11) have found 8 abandoned <br />adits which are continuously draining, 2 in the central zone, <br />3 in the intermediate zone, and 3 in the peripheral zone. <br />The ranges in concentration of various elements for the <br />drainages from each zone are listed in Table II, and these <br />ranges highlight the zonal changes in the water chemistry. <br />The most important conclusion that is shown by the zonal <br />0 <br />