Gold mineralization at the Ketza River Mine occurs in massive manto replacement deposits along preferred horizons within Lower Cambrian limestone. Primary economic deposits occur on the south flank of the Ketza Uplift, postulated to be related to a Cretaceous buried intrusion. The Ketza Uplift appears to be associated with a major gold-bearing alteration system, with potential for large disseminated and stringer-stockwork type gold deposits in Lower Cambrian clastic rocks. On the Ketza River property, the structural setting and mineralogy of the Shamrock zone is suggestive of the Carlin-type deposits of Nevada. This zone has undergone the same strong deformation as the manto deposits but further structural mapping is necessary to define the gold distribution. Future plans include re-mapping the property and re-interpretation of the structure.

The Ketza River polymetallic mineral deposits are situated in the Pelly Mountains, Central Yukon Territory. The deposits were mined for gold from 1988 to 1990, producing 400 tomes of oxide ore per day over that period. The Ketza River deposits are hosted by lower Paleozoic sedimentary strata of the parautochthonous Cassiar Terrane. The main host to economic mineralisation is a lower Cambrian, massive, areheocyathid-bearing limestone, which outcrops over much of the Ketza River area. Four styles of mineralisation are recognised within the Ketza River deposits. Type I mineralisation occurs in the centre of the area and consists of argillite-hosted, Au- quartz-sulphide veins. Sulphide mineralogy is mainly arsenopyrite and pyrite. Type II mineralisation consists of limestone-hosted, massive sulphide mantos and chimneys. The principal sulphide mineralogy of the mantos is pyrrhotite-arsenopyrite-pyrite-chalcopyrite, with quartz and calcite gangue. Gold is present within the arsenopyrite and pyrite. Type III mineralisation consists of limestone-hosted, quartz-sulphide veins and mantos. Mineralogy is similar to the Type II mineralisation, but contains a higher proportion of gangue. Type IV mineralisation consists of Ag-Pb veins. These veins are hosted by a variety of lithologies and represent the outermost extent of Ketza River mineralisation. Sulphide mineralogy is galena-sphalerite-pyrite, with siderite, calcite and quartz gangue. Oxidation of sulphides in parts of the Ketza River area is deep and pervasive. Areas of oxidation show increased gold grade and were the focus for mining. Oxidation occurs in the heavily fractured central area of the mineralisation, and along the Peel Fault, which extends from the centre of mineralisation towards the east. Light stable isotope studies indicate that the main mineralising fluid was of meteoric origin (delta (18)Ofluid = 10 per mil, delta Dfluid = -165 per mil). This fluid had evolved in delta (18)O by interaction with Cassiar Terrane rocks before mineralisation occured. Fluid flow in the limestones was pervasive, and produced a large, approximately 75km(2), (18)O depletion halo around the deposits. The later oxidising fluid was also of meteoric origin (delta (18)Ofluid = 18 per mil) but shows no evidence of interaction with the sedimentary pile. Fluid inclusion microthermometry suggests that the temperature of formation of the deposit was around 325 degrees C, at pressures above 600 bars. The mineralising fluid contained approximately 11 mole% CO2+ or -CH4, and 5 equivalent weight% NaCI.

Map and report listing information on 419 mineral ocurrences in Yukon that contain noteworthy amounts of gold and/or silver. A capsule description of the occurrence's geology is present along with a list of the significant ore minerals. This is followed by information on the metal content of the occurrence and extent of exploration and development work. Accompanying this report is a 1:2,000,000-scale map of gold-silver deposits and occurrences in the Yukon Territory.

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One third of the gold and gold-silver deposits in Yukon were examined and sampled in 1980 to establish a framework of geology and rock chemistry from which variations within and between deposits could be detected and evaluated. Lithologic units within the samples were analyzed for Au, Ag, B, Mn, Cu, Zn, As, Se, Tl, Pb, Bi, Sb, Te, W, Hg, Mo and Cd - elements commonly associated with precious metal deposits. A problem which prevented systematic sampling of many deposits is the lack of underground access and the locally intense oxidation of vein outcrops. Three aspects of the rock geochemistry are discussed:: 1) different levels of element concentration in the deposits and implications regarding pathfinder elements; 2) distribution of elements in deposit types; and 3) element distribution in specific deposits. The geology of the deposits is summarized from published works and interpreted in light of recent theories on gold deposits. This report emphasizes common features of the deposits and several genetic models.

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Detailed exploration conducted during 2006 in the western part of the Skukum Creek deposit has revealed new structural, mineralogical and geochemical features. The deposit incorporates a number of (at least six or seven) sub- parallel narrow mineralized zones, coincident with andesite-dacite-rhyolite dyke swarms extending for at least 1 km along strike and for hundreds of metres down-dip. Various mineralized zones differ in size, structural setting, intensity and composition of mineralization, and, in total, form a large mineralized package more than 200 m wide, corresponding to a property- to district-scale fault zone extending for over 10 km and traced by a dyke belt. Significant potential exists for the exploration of these structures along strike and down-dip. The diamond drilling intersected numerous high-grade intercepts of gold and silver mineralization corresponding to the low-sulphidation sub-type of epithermal gold-silver deposits. However, strong enrichment in base metals (up to 25% of combined Zn+Pb+Cu) and arsenic suggests essential differences from typical epithermal mineralized systems.

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The Stu copper-gold±silver occurrence (Yukon MINFILE 115I 011) is located midway between the Minto and Carmacks Copper deposits in the eastern, Minto suite portion of the Granite Mountain batholith. The best known mineralization at Stu is in Zone A, where at least four foliated and mineralized bodies strike northwest and dip moderately to steeply to the northeast. These bodies grade 0.2 to 0.6% total Cu, though the best historic diamond drill intersection contains 3.5% Cu over 13.5 m. In plan and cross section view, the foliated and mineralized granodioritic orthogneiss bodies pinch and swell, appearing as lenses surrounded by unfoliated K-feldspar porphyritic granodiorite. Copper mineralization occurs as both fine-grained hypogene bornite and chalcopyrite, and supergene malachite, azurite, tenorite and chrysocolla. This study suggests that Stu mineralization is similar to that at the Carmacks Copper and Minto deposits as it is primarily hosted in multiple, discrete bodies of foliated granodioritic rock. In terms of ore body orientation, the moderate to steeply dipping nature at Stu is more reminiscent of Carmacks Copper than Minto, which likely explains the presence of significant supergene copper mineralization.

The Stewart River map area (115 O&N) is the most important historic and current placer gold producing region in the Yukon. Unfortunately, the historic placer-gold deposits are becoming depleted, and more efficient mining of existing deposits and exploration for new deposits must be encouraged. Although placer deposits in the Klondike district are well described and their origin is quite well understood, placer deposits in the remaining part of the Stewart River map area have not been so well documented. The purpose of the Stewart River placer project is to describe and document the geology of known placer deposits, to interpret the formation of the placer deposits, and to relate the geology of the placer deposits to the regional surficial and bedrock geology. The objectives of the project are to aid in the exploration and mining of placer deposits by providing a comprehensive and up-to-date placer geoscience database. The utility of the placer database is that it can be used to construct placer deposit models (general summaries of given placer settings). These models then serve as predictors for future placer exploration and mining. Fieldwork for the project began in 1998 and will be completed in 2001; results of the project will be published in a final report and a resource appraisal map for placer gold.