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Virgin Mountain - Rare Earths
Mohave County, AZ, USA
Updated January 2023
Location
The Virgin Mountain rare earth & beryllium property is located in the Arizona portion of the Virgin Mountain range, about 120 km northeast of Las Vegas, Nevada. Globex staked 6 unpatented lode claims (VM-1 to VM-6) in May 2022 and additional 17 unpatented lode claims (VM-7 to VM-23) in December 2022, totalling 23 lode claims. Each claim is 457 m (1500 feet) long and 183 m (600 feet) wide (20.66 acres or 8.36 ha), totalling a surface area of 192.28 ha. The prospect area is situated in the eastern part of the western Virgin Mountain range, just west of the Lime Kiln Canyon (usually a dry river bed). Elevations range between 1050 and 1700 m. It is easily accessible from Las Vegas via highway 15 toward the northeast until the village of Mesquite, NV, from here a 16 km long gravel road leads to the prospect area. Total driving distance is about 180 km.
Location map for Globex’s Virgin Mountain project
Geology
The Virgin Mountains represent a northeast trending range, consisting of a core of Precambrian (1.7-1.8 billion years) metamorphic and intrusive rocks, flanked by Paleozoic to Cenozoic sedimentary rocks. Rocks occurring in, or in the vicinity to the property area include felsic migmatite, ortho- & paragneiss, basic & ultrabasic metamorphics, schist and pegmatites. Meta-igneous and meta-sedimentary rocks exhibit intense shear deformation and evidence of high temperature/high pressure and possibly ultra-high pressure metamorphism.
Preliminary geologic map for the central Virgin Mountains, Arizona depicts areas or continuous structures/zones exhibiting anomalous high radioactivity levels. Also shown on the map are samples collected outside the Hummingbird REE Zone and the Globex claim block (claims VM-1 to VM-23).
History
Past exploration activities for uranium and later for rare earth elements (REE) initiated in the 1940’s and ended in 1991. Numerous small exploration pits, one collapsed adit, 2 collapsed shafts and a number of old access roads resulted from these exploration efforts. During that time several companies conducted exploration work, including American Smelting and Refining Company (ASARCO), which sank a 25 m deep shaft and finally the Blandsell Mining Company, abandoning the area in 1991. In the 1950th and 1960th the Virgin Mountains Be-bearing pegmatites had been explored intensely for beryllium, but never came into production, due to the discovery of the world-largest Spor Mountain beryllium deposit (western Utah) in 1959.
Photo of the westernmost Hummingbird REE Zone, viewing south. In the right centre a 1.5 m deep and 5 m long exploration cut (sample AGL-8), further west 2 exploration pits (sample AGL-13) and a collapsed adit.
Sample Preparation & Assay Methods
Samples were placed in labelled plastic bags, sealed with a plastic zip and shipped to American Assay Laboratories (AAL) in Sparks, Nevada, USA for preparation and geochemical analysis. AAL is an ISO 17025 certified laboratory. Samples are crushed and a 300 g subsample pulverized. All samples underwent ICP-OES/MS analysis of a 0.5 g sub-sample after 5-acid digestion for 60 (61) elements including silver and all rare earth elements (Assay lab code: ICP-5AM60 or IO-4AB61). For samples assayed for Beryllium a 0.5 g sub-sample is digested via sodium peroxide fusion followed by ICP-OES (lab code: IO-NFBe). Typical internal standards and checks were completed by AAL during analysis.
It should be noted that 5-acid digestion method might not dissolve all REE-bearing mineral phases completely, also columbite (niobium-tantalum mineral), beryl and chrysoberyl are not well dissolved with the 5-acid method. For the future it is strongly recommended in assaying REE and all other elements with sodium peroxide total digestion followed by ICP-OES or lithium borate fusion and XRF analysis
Rare Earth Element Uses & Demand
According to the Critical Minerals Institute (criticalmineralsinstitute.com) highest future demand can be expected for the LREEs neodymium and praseodymium and the HREEs dysprosium and terbium. The REE are essential raw materials for a wide range of applications, including metallurgy (metal refining and metal alloying), catalysts in the automotive and the petro-chemical industry, colouring of glass/ceramics, phosphors (LEDs, compact fluorescent lamps, flat panel displays), lasers, rechargeable solid state batteries (Ni-MH), fibre optics and others. Additionally, REE are vital elements in emerging technologies such as solid state fuel cells, superconductors, magnetic cooling, hydrogen storage and high performance permanent magnets. The latter are crucial in a variety of high-tech applications ranging from wind-turbines and hybrid cars to HD drives and cell phone speakers and microphones Magnets and catalysts are the most-significant applications in the rare earth metals industry.
Virgin Mountain REE-(Th+U) Mineralization
The principal REE mineralization, named herein the Hummingbird Zone, could be followed-up over a distance of 250 m. Sampling and preliminary detail mapping, also with help of a scintillator radiation detector, defined steeply dipping parallel and en-echelon mineralized zones along a 30-40 m wide corridor trending in average 65° NE. Strong faulting, shearing and brecciation can be observed in some of the mineralized structures, mostly concordant to foliation of the metamorphic wall rock, chiefly felsic migmatite-gneiss. Rare Earth mineralization is associated to elevated radioactivity caused mainly by thorium and less uranium. Principal ore minerals are probably the phosphate minerals xenotime and monazite.
Due to slope scree and shallow overburden entire mineralization width is in most outcrops not exposed. Globex confirmed minimum high-grade widths (with assays) between 0.9 m and at least 1.45 m, however widths of radioactive anomalies related to REE mineralization may approach 5 to over 10 m width (full widths not yet sampled). Globex collected 7 channel samples from outcrops of the principal REE structural trend. The Hummingbird Zone is open to the east (300 m additional length are possible), where it is concealed by rather shallow fluvial sand and gravel (1-3 m?). Lateral extension for about 300 m to the west is possible as well, where most of the structure is hidden under shallow overburden and slope scree.
REE + U, Th assay results for 7 channel samples collected at the Hummingbird Zone
All 7 channel samples collected from the Hummingbird structure at the Virgin Mountain project returned considerable high grades of light (LREE) and heavy (HREE) rare earth elements ± thorium and uranium. Total Rare Earth oxide contents (TREO) vary between 0.328% and 1.24%. Thorium contents (up to 828 ppm) are 3 to 8 fold higher than uranium contents. Uranium could represent a by-product of the REE mineralization; higher grades below the oxidation level can be expected.
Preliminary close-up geologic map of Hummingbird REE Zone with sample locations. Depicted are the historically mapped REE structure (Blandsell Mining Company exploration in 1990) and the REE mineralisation defined (so far) by Globex.
The Humingbird Zone sticks out with enrichment of the (more valuable) heavy rare earth elements against most other worldwide REE deposits/occurrence (except similar Wolverine deposit in Australia). These elements include the high-value HREE gadolinium, terbium, dysprosium, holmium, erbium, lutetium (and even thulium). Furthermore mineralization contains abundant yttrium (lower value), ytterbium and the valuable LREE neodymium. Terbium is the most valuable HREE (2231 USD/kg Tb2O3, March 18 2022), assays returned up to 96 g/t (0.01%) Tb2O3.
Numerous additional radioactive anomaly zones have been preliminarily mapped at the Virgin Mountain project, but only 12 samples have yet been collected from these anomalies. From these 12 samples 5 samples returned elevated REE values. Most of these anomalies appear to carry only low uranium and thorium values, however low-grade REE mineralization (up to 910 ppm TREO) was discovered at the at least 60 m long and 5-6 m wide Hummingbird West B anomaly (600 m west of Hummingbird Zone) and at the at least 400 m long Hummingbird West A anomaly (located 1.5 km west of the Hummingbird Zone). Significant additional exploration potential is given here.
Meanwhile carbonatites are the world’s main source for the LREEs, Ion-adsorption clay deposits in southern China are the world’s primary sources for the HREEs. However hydrothermal REE deposits are getting increasingly important and could become the prime source for HREEs in the future years. Most advanced project is the hydrothermal-unconformity related high-grade Wolverine deposit (Browns Range) in Western Australia. It is owned and operated by Northern Minerals and started test mining in late 2018. In a pilot plant had been produced HREE-carbonate until March 2022. The company intends to produce and market products of Dysprosium, Terbium and Yttrium. Lode-, breccia- and stockwork/disseminated-mineralization is hosted in Precambrian metamorphic rocks with the principal ore mineral xenotime. The total indicated & inferred mineral resource is estimated at 9.24 Mt @ 0.67% TREO with 0.57 kg/t Dy2O3, 0.08 kg/t Tb4O7 and 3.81 kg/t Y2O3. These grades are similar to those assayed at the Virgin Mountain project (Hummingbird Zone), however at Virgin Mountain also significant neodymium and some praseodymium is present.
The deposit type of the HREE-dominated mineralization at the Hummingbird Zone, Virgin Mountain Project is not yet well understood, could however represent a combination of pre-metamorphic enrichment in protolith rocks and hydrothermal processes.
Beryllium (Nb, Ta) Opportunity at Virgin Mountain Project
Pegmatites, up to 6 m thick, highly enriched in beryllium occur within the Globex claim block over a strike length of about 2.5 km. These are hosted exclusively in a narrow mica-schist belt and in intercalated amphibolite or hornblende-biotite-schist. Pegmatites are composed of feldspar (microcline, albite, plagioclase), muscovite, locally garnet, in places minor tourmaline, beryl and/or chrysoberyl. In addition to beryllium these pegmatites carry locally also minor amounts of the critical metals niobium & tantalum. I n the 1950’s and 1960’s BeO grades had been analysed from 135 rock samples (bulk, channel and grab) with a berylometer instrument at the Reno Metallurgy Research Center. BeO grades ranged widely between 0.02% and 2.98%, corresponding to Be values between 72 ppm and 10,736 ppm. Globex collected four samples from these pegmatites, they returned between 325 and 7,577 ppm beryllium.
Assay results of chrysoberyl-bearing pegmatite dikes.
In contrast to most other Be-bearing pegmatites in the world the dominant Be-mineral in the Virgin Mountain pegmatites is chrysoberyl. Chrysoberyl (formula: BeAl2O4 ) occurs mostly as subhedral to euhedral tabular yellowish-green crystals up to 3 cm in size. Chrysoberyl contains 7.1% Be (against 5.03% Be in beryl). The average densitiy of chrysoberyl is 3.67 g/cm3 (in contrast to beryl with 2.76 g/cm3). Consequently it is possible to concentrate chrysoberyl by a simple gravity process. That is not possible with beryl, beryl must be separated either by hand-cobbing or by flotation.
Nowadays the mineral bertrandite is the source mineral for more than 90 percent of the beryllium produced globally. Spor Mountain, the world-largest beryllium deposit, located in the state of Utah, USA produced about 170 tons beryllium from the total yearly worldwide production of 260 tons in 2021. However the bertrandite ore from Spor Mountain is not suitable for ultra-high-purity beryllium products, due its high content of F and U. Ultra-high-purity beryllium is made exclusively from the mineral beryl (formula: Be3Al2Si6O18 ).
In the case that it should be also possible to extract high-purity beryllium from a chrysoberyl concentrate, Globex’s Virgin Mountain Be-pegmatite field would represent a rare opportunity for cost-efficient production of very high-purity beryllium. Instead of a costly pyrometallurgical method, as used for beryl-ore, beryllium from chrysoberyl concentrate could be dissolved and subsequently extracted via use of a low temperatures hydrochemical method. The BeO cut-off grade at Virgin Mountain could be much lower than that at Spor Mountain (here entire ore must be milled and acid-leached) as a chrysoberyl concentrate can be obtained via low-cost gravity-magnetic separation. A cut-off grade around 300 ppm Be might be sufficient. In addition Nb and Ta could be recovered as by-products, as well as quartz, flake-muscovite and feldspar.
In 2020 in the USA the average price for 1 kg of beryllium metal (contained mostly in beryllium-copper master alloy) was 647 USD (Gustavson Assoc. 2022). Beryllium metal (> 99%) was listed at 1093 USD/kg on the Shanghai Metals Exchange on January 20, 2023 (metal.com). For high or ultra-high purity beryllium (>99.7% to 99.999% Be) prices are far higher. It appears likely that the demand for high-purity beryllium will rise considerably due to increased use in newest generation nuclear energy plants and increased demand by multiple industrial applications.
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Direct Contact - Jack Stoch:
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E-mail: [email protected]
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