2010-03-16_REVISION - M1981185 (29)

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Wildcat Mining Corporation Page 27 • Quartz is the predominant gangue mineral in all veins; lesser quantities of ankerite, barite, clay or other minerals may be present. The ore minerals, including most of the known telluride minerals and free gold are very erratically distributed even within ore shoots. The ore minerals may occur as irregular masses within the quartz or commonly occur as thin dark threads and veinlets in the quartz. In the May Day mine, telluride minerals and gold also occur as a fine dark coating on fracture surfaces within altered sandstone wall rock. As is common in many mines in the La Plata District, some if not all of the high - grade ore shoots within the main vein zones are controlled by abrupt changes in the dip or strike of the vein, as illustrated in figure 7. As well, the thickness and grade of veins is related to the physical character of the wall -rock. Where host rocks are more competent (sandstone and limestone) the veins are wider and better developed; incompetent rocks (shale, siltstone and mudstone) host narrow, poorly developed veins. By far the greatest portion of the ore produced was found where one or both vein walls were Entrada or Junction Creek sandstone. Some of the richest ores that have been produced in the district have been from limestone replacement deposits. These deposits consist of the total to near -total replacement of host limestone by ore minerals, including the tellurides and native gold. All of these deposits occur in the Pony Express limestone adjacent to productive veins. Few replacement deposits extend more than 50 feet from a fissure and in general the tenor of ore decreases with distance from the vein fissure. The altered porphyry of the Idaho dike near the intersection with the May Day vein deserves more attention. The dike ranges in width from 8 to 25 feet and in the vicinity of the vein is brecciated and clay - altered. Both McCausland (1941) and Eckel (1949) report this material in places to have contained 0.4 -0.5 opt gold. It is said that the May Day Milling Company mined and milled some of the dike from the May Day #2 level, but there is no documentation of this. Disseminated gold deposits escaped the attention of underground miners elsewhere in the past, and such may be the case here. The interrelationship of stratigraphy, structure, and igneous rocks in controlling the location and style of mineralization within the May Day mine is illustrated in figure 8. • January 2007 May Day — Idaho Mine Colorado