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February 7, 2007 <br />-4- 063 -2140 <br />openings, or cone shaped excavations were also labeled as collapsed shafts if the <br />features were located where historical records indicate shafts. <br />• Adit — A horizontal or nearly horizontal opening into a hillside, following a <br />mineral vein and/or providing access other drifts. In the field, many adits were <br />timbered around their openings, though some were not. Openings were typically <br />approximately 5 feet high and 3 to 4 feet wide. Significant development rock <br />piles were often present around the opening. <br />• Collapsed Adit — A feature which, based on field observations and/or historical <br />mining records, is likely to have been an Adit (but is now caved in or collapsed). <br />In some cases, the timbering around the opening of the adit remained intact. In <br />other cases, a large waste rock pile is visible near the previous adit opening, and <br />a linear depression extends upslope. <br />• Slot Mine — A narrow, planar feature open at the surface caused by mining a <br />mineral vein from the surface. The features are roughly vertical, though they <br />have different orientations depending on the strike /dip of the mineral vein. They <br />are usually 2 to 5 feet wide, but some features (Anaconda) are much wider (up to <br />20 feet). <br />• Open /Collapsed Stope — Generally a roughly vertical, irregular shaped opening <br />created by mining a mineral vein from a drift all the way up to the surface or by <br />collapse of the cap rock above a stope not originally mined to the surface. These <br />features often have visible support timbers, and may or may not have large waste <br />rock piles associated with them. Often stopes are difficult to differentiate from <br />slot mine features. <br />• Depression — Roughly circular or linear sinkholes or depressions which may <br />indicate the collapse of underlying stopes, drifts, or other mine workings. <br />• Trench — Shallow, linear excavations usually 2 to 6 feet deep. The intended <br />purpose of these features is not often clear. They may be prospecting features. <br />2.3.2 Features Observed within Squaw Gulch <br />This section provides an overview of the numbers and types of historical mining features observed <br />within the proposed Squaw Gulch VLF footprint. In the field, many of the features observed were not <br />easily placed into a single category. For purposes of this summary discussion, conservative <br />assumptions were made regarding feature categorization. For example, if a conical excavation was <br />observed with a small to moderately sized development rock pile and a single board or timber in the <br />bottom of the excavation, it would be classified as a collapsed shaft, not a test pit. The feature <br />designations are shown on Drawing 1. The feature descriptions presented in Table 1 provide more <br />detail with any uncertainty in the feature's classification noted. The photographic log can also be <br />used as a reference to get a more accurate idea of what was observed in the field. <br />BO S 21W0100W1111316TWORKR1GSNLOT£EBO'MW I1LTTORICALWON.INGS- FTIA9FE007 DpC Golder Associates <br />