Moon River Moly Ltd. is the holder of the exclusive right of access to and from, and to enter upon and take possession of and prospect, develop and mine the Davidson Property, and holds the right to remove and ship therefrom all ore, bullion, concentrates, and minerals recovered in any manner from the Davidson Property all subject to the provisions of the Davidson Agreement with Roda.
All claims and leases are contiguous and registered to the name of Roda Holdings Inc.
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Summary:
The Property is a molybdenite-scheelite porphyry deposit 2.5 km across and extending up to 2 km in depth that consists of moderately to steeply dipping stockwork veins ranging from hairline to 5 mm in width.
Deposit Type
The Davidson deposit is a porphyry molybdenum deposit that shares similar characteristics to the Climax type of molybdenum deposit including mineralised quartz-rich felsic intrusions, multiple mineralisation shells, uni-directional solidification textures, and geological setting (continental back-arc spreading environment). Westra and Keith (1981) classified the deposit as a subset of the Climax type, transitional toward calc-alkaline molybdenum stockwork deposits. Examples of deposits of this transitional type include Questa in New Mexico, USA and Mt. Hope in Nevada, USA. Available geochemical data indicate that the Davidson deposit is characterised by lower fluorine contents than those typical for a Climax type porphyry molybdenum deposit. Bright (1972) reported about 0.1% fluorine in the mineralised zone and about 0.05% fluorine below the mineralised zone, with localised elevated values of up to 2.7% fluorine. Atkinson (1981) reported less than 0.1% fluorine (0.013% to 0.042%) in 9 samples from the known rhyolite plug; there may be other plugs.
The Davidson molybdenum-scheelite deposit is considered to be one of the British Columbia Porphyry molybdenite deposits that are postaccretion and range in age from 138 to 8 million years.
Mineralization
The two main zones of molybdenite mineralisation, within the Davidson deposit, have been named the Main and Lower zones, respectively. These are high-grade zones within a much larger but lower grade zone defined by the =0.17% MoS2 shell.
The mineralised zone is located inside Hudson Bay Mountain between the 940 m and 1,440 m elevations.
Main Zone
The Main zone is hosted by the granodiorite sheet and is defined by the =0.3% MoS2 grade shell. It is an irregular zone, roughly circular in plan view and elliptical in cross-section, with maximum horizontal dimensions of approximately 450 m and maximum vertical extent of approximately 200 m.
The general mineralised zones within the granodiorite, including the Main zone, has been described by Atkinson (1981) who reported two basic types of molybdenite-bearing quartz veins: Type 1 (fine-grained molybdenite) and Type 2 (coarse-grained molybdenite). The Type 1 veins are sub-divided into two subtypes: an early set of narrow (= 3 mm) veins that locally form stockworks and a set of much wider (= 60 cm) banded veins. The strongest set of banded veins dips to the southeast and east of the 15000 E crosscut, but progressively flattens to the northwest. Type 2 veins are up to 15 cm in width, carry molybdenite crystals = 5 cm in diameter, and may have been the latest quartz-molybdenite veins to be deposited.
Lower Zone
The Lower zone, as presently defined, was deposited mainly in the upper part of the rhyolite plug within the = 0.3% molybdenite grade shell. With work still in progress, the zone appears to be elongated to the north-northwest with that dimension being approximately 250 m, and with a maximum width and height of approximately 100 m and 40 m, respectively. Both fine-grained and coarse-grained quartz-molybdenite veins occur in the Lower zone, although the vein type distinctions reported in the Main zone are not as clear in this zone, and the very coarse Type 2 veins are not present. The strongest molybdenite-bearing quartz veins are banded veins, interpreted to be gently southeasterly dipping, which continue past the plug to the southeast. Disseminated molybdenite is present in small amounts locally. There is a multiplicity of vein types still under study in the general area of the Lower zone, including early barren quartz veins, molybdenite-bearing veins with or without magnetite, pyrite or scheelite, and late pyrite-carbonate and finally carbonate veins.
Altration
A Hornfels aureole, characterized by development of radiating and zoned clots and veins of garnet, epidote, chlorite, Biotite, hornblende and amphiboles, extends from surface where it has been mapped over an area 7 km by 4 km. Brown to red andradite garnet intergrown with quartz, chlorite, sericite, magnetite, carbonate and occasionally scheelite and rimmed by Epidote becomes increasingly common with depth. In some underground exposures of the sill, 30% of the wall rock is replaced by garnet clots to 10 cm across producing a spotted (appaloosa) texture.
Primary igneous textures of the sill have been obliterated by the pervasive loss of mafic minerals and the development of chlorite ± magnetite pre-molybdenite hairline stockworks, clots and veins that may in part be attributed to hydrothermal alteration.
Astride the contact of the rhyolite plug with Hazelton Group volcanic rocks and the granodiorite sill, quartz stockwork veins coalesce to form a high silica zone that mimics the shape of the top of the plug. The high silica zone averages 40 m thick and contains trace fluorite, topaz, magnetite and Biotite.
Hydrothermal alteration is fracture controlled. Vein alteration haloes rarely exceed a metre in width. Where veins are numerous, overlapping haloes form zones of pervasive alteration but deposit scale zonation has not been established. Within Hazelton Group rocks, hydrothermal alteration includes Na metasomatism, silicification and destruction of mafic minerals resulting in bleaching of the lithologies. Within the granodiorite sill alteration includes the development of pink potassic alteration which envelops magnetite, quartz, stockwork molybdenite, and pegmatitic quartzmolybdenite veins. Three pulses of hydrothermal fluids are interpreted from the cross-cutting relationships of the alteration envelope.