New York Canyon Mine, Santa Fe District, Gabbs Valley Range, Mineral County, Nevada, USAi

Regional Level Types
New York Canyon Mine	Mine
Santa Fe District	Mining District
Gabbs Valley Range	Mountain Range
Mineral County	County
Nevada	State
USA	Country

Alteration: oxidized ore minerals

Commodity: Ore Materials: malachite, azurite, chrysocolla, copper wad (oxide) , locally hematite, with minor chalcopyrite, bornite, scheelite Gangue Materials: garnet, epidote

Deposit: The geology of the Longshot Ridge deposit is relatively simple and consistent. The host rocks of the copper mineralization are a flat lying sedimentary sequence of siltstone, dolomite and limestone. The copper mineralization and associated 'skarn' alteration are related to and a result of intrusive felsic porphyry sills and dikes. The Longshot ridge zone is predominantly copper oxide copper mineralization consisting of secondary copper minerals such as malachite, azurite, chrysocolla and copper wad (oxide) with minor chalcopyrite and bornite. The strongest, thickest and most continuous mineralization occurs in a NE trending band that is crossed by two NW trending, structurally controlled zones of enrichment. An elliptical-shaped deposit lies under a ridge and measures about 1,500 ft long, 700 ft wide and up to 420 ft thick. Near the iron deposit the dolomite strikes N50E and dips 60NW. It is complexly folded and faulted. The rocks have been cut and metamorphosed by granitic rocks, the nearest exposure less than 300 feet from the deposit. The iron ore is believed to be related to the granitic rocks. Adjacent to the granitic contact, the limestone has been altered to a narrow zone of tactite exposed in outcrop for distance of 400 feet. In this altered zone scheelite mineralization occurs associated with garnet, epidote, quartz, and minor pyrite finely disseminated in shoots 3 to 6 feet wide at minor fault intersections. Mineralization at the New York Canyon property consists of three principal copper prospects along a west-northwest structural trend: Copper Queen on the west, Champion in the center and Longshot Ridge on the east. The Copper Queen prospect has no exposed mineralization at the surface but contains copper sulfide skarn at depth and an incompletely confirmed copper-molybdenum sulphide porphyry system at greater depth. The Champion and Longshot Ridge prospects, however, have numerous widespread exposures of copper skarn mineralization, both in surface outcrop and abundant old mine workings. The majority of recent exploration efforts on the New York Canyon property have focused on the extensive oxide copper skarn mineralization at Longshot Ridge. This mineralization is the subject of the current report. The copper mineralization and associated alteration at Longshot Ridge are products of an extensive copper-rich skarn system formed in carbonaceous sediments of the Luning, Gabbs and Sunrise Formations. Small amounts of copper occur also in stockwork veinlets in felsic porphyry intrusive sills and dikes. The copper mineralization consists almost entirely of secondary copper minerals, principally malachite, azurite, chrysocolla and copper wad, in order of abundance. Additionally, some copper-rich limonite (goethite) has been reported. The oxide copper minerals apparently are the products of supergene weathering and oxidation of primary copper sulphide minerals present in the original skarn. Because limestones tend to buffer any solution carrying copper in the supergene environment, copper can be enriched as much as 300 to 400 percent by this supergene weathering process. Oxide copper deposits formed in a similar manner in many copper districts throughout the southwest US, have contributed substantially to the copper produced from the associated primary copper deposits in these districts. About 90 percent of the Longshot Ridge mineralization is within the two upper units of the Gabbs Formation. Drilling reveals that the strongest, thickest and most continuous mineralization occurs in a NE-trending zone, 200 feet wide by 1300 feet long, which is crossed by two NW-trending structurally-controlled high grade zones, each about 100 feet wide and from 400 to 700 feet long.

Deposit type: Porphyry Cu, skarn-related

Development: The New York Canyon property has a long history of exploration, development and production dating back to 1875 when the copper oxide deposits were first discovered. The first recorded production from the district occurred between 1906 and 1929 when the Wall Street Copper Company consolidated various holdings of copper deposits in the district and exploited the Anderson, Champion, Mayflower, New York, Turk, Vacation and Wall Street Mines. The company produced an estimated 8.9 million pounds of copper from approximately 110,000 tons of ore with an average grade of 5.5% from a number of small surface showings in the Longshot Ridge area. Exploration of the property during the late-1960s to mid-1970s was conducted by senior mining companies exploring for major copper porphyry deposits. This work defined mineralization at both the Longshot Ridge copper oxide zone and Copper Queen copper sulfide porphyry prospect. Further exploration of the New York Canyon property was conducted between 1992 and 1997, focused primarily on the Longshot Ridge copper oxide prospect. Claims covering the New York Canyon prospects lapsed in 1999. New claims were staked by two individuals and subsequently acquired by Nevada Sunrise. Aberdene acquired an option on the property from Nevada Sunrise in March, 2004. Aberdene has completed two drill programs on the property, primarily focused on defining the extent of mineralization at the Longshot Ridge zone. Approximately 181 drill holes totaling 127,933 feet have been completed on the New York Canyon property, including the drilling by Aberdene. In 2006, Aberdene increased the size of the New York Canyon property by staking an additional 550 mineral claims to cover mineral prospects, possible leach pad areas, access routes and power line right of ways. The project will be the focus of an extensive exploration program in 2006 to further evaluate the mineral potential of the property. Activities planned include delineation and expansion drilling of the Longshot Ridge copper oxide system, metallurgical testing of the host mineralized rock and environmental base line studies to initiate a scoping study. The recently staked claims increase the total property area controlled by Aberdene to 1,003 claims covering more than 20,000 acres. In 2006, Aberdene Mines Ltd. announced that recent drill results at the New York Canyon/Longshot Ridge Project include 22-305 feet @ 0.77% Cu (05-7C); 135-260 feet @ 0.40% Cu (05-19); 50-235 feet @ 0.41% Cu (05-21C); 0-70 feet @ 0.29% Cu (05-24) and 0-80 feet @ 0.38% Cu (05-25). (resource = 16,100,000 tons @ 0.55% Cu)

Geology: Regional geology- The New York Canyon Project lies within the central portion of the Walker Lane structural belt, a broad zone of northwest-southeast striking parallel to sub-parallel, right lateral strike-slip faults extending for more than 400 miles through western Nevada and into northern California. The structural belt was initiated during the Jurassic period, at which time a number of important porphyry copper deposits and related skarn deposits, such as Yerington, were formed. Volcanism and related hydrothermal mineralization, often of Tertiary age, are recognized along the length of this structural trend. Significant mining districts associated with the Walker Lane Belt, in addition to Yerington, include Comstock, Goldfield, Rawhide, Tonopah-Hall, Dome Hill and numerous other copper and/or gold-silver occurrences. The New York Canyon area stratigraphy is comprised mostly of conformable marine sedimentary units of Triassic and Jurassic ages which are intruded by granitic rocks of Cretaceous age. Tertiary-age non-mineralized volcanic flows locally cover these older rocks on the hills and Quaternary-age alluvium and colluvium cover them in the valleys. At New York Canyon, the rocks are disrupted by structures mostly related to the Walker Lane structural belt. These structures provide conduits for mineralizing fluids and often subsequently disrupt mineralized zones. The oldest rocks belong to the middle to late Triassic age Luning Formation, consisting predominately of dolomite, dolomitic limestone and limestone with minor shale, argillite and conglomerate. Project mapping and logging of drill holes indicate this sequence is approximately 2000 thinner in the Project area than its regionally mapped thickness of more than 10,000 feet. The Luning limestones are thin to medium bedded and intercalated with siltstones in the bottom 1000 feet of the sequence, and massive to thick bedded in the top 4000 feet of the sequence. The late Triassic age Gabbs Formation conformably overlies the Luning Formation. The Gabbs Formation consists of three members: a thin bedded fossiliferous limestone, argillaceous limestone, and calcareous tuffaceous siltstone. The type locality of the Gabbs Formation is in New York Canyon, where its thickness is measured as 400 feet, but drill logs indicate it is up to 650 feet thick. The Jurassic age Sunrise Formation conformably overlies the Gabbs Formation. The Sunrise Formation consists of five members with quartz latite porphyry flows near the base overlain by thin bedded limestones, siltstones, silty limestone, tuffaceous siltstone, shale and claystone totaling about 800 feet in thickness in the New York Canyon area. The Jurassic age Dunlap Formation conformably overlies the Sunrise Formation. The Dunlap Formation is a 3000-foot thick sequence of basal conglomerate, limestones, clastic sediments, and volcanic flows of andesitic and rhyolitic composition. The strata of New York Canyon are intruded by Jurassic to Cretaceous age multiphase domes, plugs, dikes and sills consisting primarily of diorite and granodiorite with areas of quartz monzonite, granite and other associated felsic rock types. Numerous Tertiary age units (mostly Oligocene and Miocene age) consisting of mafic to felsic volcanics, volcanoclastics, flows, tuffs, tuffaceous sediments, and continental sediments locally overlie the older rocks. These lithologies are of varying thicknesses ranging from 100s of feet to more than 1000 feet. Quaternary age deposits consisting of various alluvial and lacustrine sediments comprise the youngest units in the area and fill the valley bottoms and form pediments along the range fronts. These young units may be 200 feet or more thick. Geology at New York Canyon: The upper New York Canyon area consists primarily of the Luning Formation which is overlain by the Gabbs and Sunrise Formations in the Longshot Ridge area. The Luning Formation exposed beneath the Longshot Ridge area consists of gray to tan colored, thickbedded limestone and dolomite. Felsic sills and dikes intrude all units in the area. The Gabbs Formation at Longshot Ridge is extremely calc-silicate altered. It was originally a very thin bedded to laminated limestone and silty limestone intercalated with siltstone and shale. The Gabbs Formation is comprised of three members: (#1) the lowest member, which is 250 feet thick, consisting of thick black bioclastic limestone intercalated with siltstone, (#2) the middle member, 200 feet thick, consisting of predominately argillaceous limestone intercalated with calcareous and tuffaceous siltstone, and (#3) the upper member, from 0 to 200 feet thick, consisting of argillaceous limestone intercalated with siltstone. The black bioclastic carbonaceous limestone at the base of the Gabbs Formation is a distinct unit which provides a clear marker for the contact with the underlying Luning Formation. The two lowest members of the Sunrise Formation at Longshot Ridge are also calcsilicate altered. The Sunrise consists of five members: (#1) the lowest member, 100 feet thick, consisting of argillaceous limestone intercalated with siltstone and some quartz latite porphyry flows near the base, overlain by (#2), 50 feet thick, consisting of thick-bedded fossiliferous limestone intercalated with siltstone and silty limestone, overlain by (#3), 250 feet thick, consisting of shale and siltstone, overlain by (#4), 200 feet thick, consisting of silty limestone and limestone, and capped by (#5), 200 feet thick, consisting of claystone and limestone. The Dunlap formation, mentioned in the previous description of regional geology, is not present in the Longshot Ridge area. Similarly, only one of the Tertiary-age volcanic sequences exists along the flank of Longshot Ridge. The intrusive rocks (Fi) on Longshot Ridge are primarily sills with some local dikes. Rock types mapped at the surface and encountered in drill holes consist of granodiorite porphyry, porphyritic quartz monzonite, quartz monzonite porphyry and quartz-feldspar porphyry. These sills and dikes are typically only 5 to 20 feet thick but are relatively common throughout the area. Rock strata on Longshot Ridge average N75?E in strike dip about 35?. The rocks are severely faulted and folded. Drag and overturned features are common. The major faults are curvilinear with fairly high dip angles that commonly change along the strike of the structure. The faults generally trend either northeast or northwest, but there are some local faults that strike north and dip steeply east. For the most part, the faults appear to have normal displacements ranging from 50 to 200 feet. Deposit Types at New York Canyon Project: Mineralization in the New York Canyon Project occurs principally as contact metasomatic copper skarn deposits and as possible copper porphyry deposits within intrusive bodies at depth beneath the skarns. Contact metasomatic deposits include a variety of types such as those that are copper-rich, ironrich, tungsten-rich, etc. The deposits are commonly referred to as skarns when rich in copper and tactites when rich in tungsten. Minerals associated with the copper-rich skarn deposits typically include chalcopyrite, bornite, magnetite, specularite, pyrite, pyrrhotite, sphalerite, and molybdenite. Alteration associated with the skarn deposits converts limestone and limy sediments to higher temperature calc-silicate minerals consisting of garnet, epidote, diopside, tremolite and calcite. Skarn deposits are always adjacent to small to moderate sized intrusive bodies of intermediate composition such as monzonite and granodiorite. These intrusive bodies ? occurring mainly as sills, dikes, plugs or stocks ? are the sources for the mineralizing and altering hydrothermal fluids and for the heat that drives the fluids. Skarn mineralization develops along specific altered beds of carbonate rock in zones of strong deformation or faulting adjacent to the intrusive bodies. The New York Canyon copper skarns closely fit these descriptions. The skarns either consist mostly of oxidized minerals, as at Longshot Ridge, or they consist of both oxidized and sulfide minerals as at the Champion prospect west of Longshot Ridge. At Copper Queen, the westernmost New York Canyon target, known mineralization, incompletely explored to date, consists of both non-oxidized copper sulfide skarns and potential porphyry-type copper-molybdenum sulfides in the underlying intrusive body. The porphyry mineralization remains an exploration target of possible large size based on (1) the widespread occurrences of oxide copper showings on the surface, (2) limited geophysical surveys, (3) apparent doming of the overlying sediments, and (4) the district?s location within the Walker Lane structural belt which hosts several large porphyry systems such as Yerington to the northwest and Hall Mountain to the southeast. Exploration targets for the project might range from 150 million to 400 million tons as grades of 0.4% to 0.5% copper with possible credits in molybdenum. Lunig Formation - these carbonates consist primarily of dolomite and limestone. Alteration associated with these rocks includes a skarn mineral suite consisting primarily of serpentine, talc, garnet, magnetite, and locally diopside. The serpentine and talc minerals in skarn form sinuous veins along the structures within the dolomite and are very diagnostic of skarn formation in dolomite. Due to the massive nature of the Luning Formation, the altering and mineralizing solutions closely followed high-angle cross-cutting structures and formed limited skarn halos with only small areas of moderately high grade copper mineralization. The Luning also has some small local zones of hematite and dolomite containing jasperoid veins a few feet thick. These consist of fine-grained silica, hematite, goethite, limonite and copper oxides. Historically, all the higher-grade copper shipped from this district during World War I was from the copper skarns in the Luning, not from the copper skarns in the Gabbs. Gabbs Formation ? The principal host for the Longshot Ridge copper skarn deposits are impure thin-bedded sandy limestone and siltstone in the upper two units of the Gabbs Formation. The alteration associated with these rocks is either a skarn mineral suite consisting of garnet, diopside and magnetite in the limestone, or is hornfels developed in the siltstone. The copper mineralization is much more widespread, but lower grade for the reasons stated in the previous Luning skarn description. The diopside-rich Gabbs skarns are more abundantly fractured and mineralized due to the brittle nature of diopside, and for this reason these skarns are slightly higher grade than the garnet-rich skarn. Commonly the Gabbs skarns are only a few feet thick (5 to 15 feet), but there are many of them. The lowest Gabbs unit, a carbonaceous bioclastic limestone, is the location of the ?marble line,? which is the alteration boundary between marbleized and calc-silicate altered limestone. This unit rarely forms skarns. The upper two units are hosts for the plentiful skarns and hornfels formed when the hydrothermal solutions traveled up structures and outward along permeable units. These same structures and permeable beds were later intruded by granodiorite porphyry dikes and sills. The intrusive bodies proximal to the skarns are most commonly sills but dikes are locally present. Sunrise Formation ? The two lowest sedimentary units of the Sunrise Formation are impure thin-bedded sandy limestone and siltstone which are altered and mineralized. The alteration occurs as either a skarn mineral suite consisting of garnet, diopside and magnetite in the limestone, or as hornfels developed in the siltstone. The copper mineralization is much more widespread, but lower grade for the reasons stated above in the previous Luning skarn description. The diopside-rich skarns are more abundantly fractured and mineralized due to the brittle nature of diopside and for this reason these skarns are slightly higher grade than the garnet-rich skarns. The skarns in the Sunrise Formation are commonly very thick (50 feet). The largest of these is the Mayflower Mine, which was mined on a fairly large scale. This thick skarn is capped by a thick hornfels.

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Link to USGS MRDS:	10310559

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References