Carp
Location, Access, Description
Globex’s Carp Fluorspar project is located in southeastern Nevada, Lincoln County, 140 km in beeline northeast of the city of Las Vegas. Globex staked a contiguous claim block consisting of 14 unpatented lode claims in March 2024. Each claim is 457 m (1500 feet) long and 183 m (600 feet) wide (20.66 acres or 8.36 ha), totaling a surface area of 117.08 ha. The entire Carp property lies on public land managed by the Bureau of Land Management (BLM) outside of any conservation area (e.g. areas of critical environmental concern or Wilderness areas).
The Carp project area is situated just north of the flat Tule Desert basin at the southern flank of the Clover Mountains with highest peaks reaching altitudes of 2000 to 2325 m. Elevations in the slightly hilly project area vary between 1240 and 1325 m. Vegetation consists of sparse bushes, grass and sporadic cactus. Climate is dry with a small average amount of rainfall during the year (mostly rain, but rarely snowfall, during the winter time). Temperatures range from moderately hot during the summer to short freezing periods in winter time.
Geology and Mineralization
Regional Geology
The historic Carp mine lies within the Viola mining district.
The Viola mining district lies just to the south of the southern margin of the huge Caliente caldera complex. Felsic and intermediate volcanic rocks erupted between 24 and 18 Ma from this complex during the Late Oligocene until Early Miocene. Andesite, latite and dacite are generally the oldest volcanic rocks, overlain by extensive felsic ignimbrite sheets. In the district appear three isolated (each several km across) windows of Paleozoic carbonate-rocks surrounded by mostly extrusive volcanic rocks erupted from the Caliente Caldera.
The southeastern carbonate-rock block, near the Carp mine and the central block, are composed of Carboniferous to Permian dolomite and limestone. Fluorite, barite, Mn-Fe and locally Ag-Pb-Zn-Cu mineralization in the southeastern Viola district (Globex’s Carp project area) are hosted mostly in carbonate sediments as replacement bodies and veins. The historic Carp mine (also called Wells Cargo mine) exploited rather large fluorite bodies from four open pits.
Project Geology and Mineralization
About 70% of the Tertiary and Paleozoic rocks in the project area are masked by a thin cover of transported gravel or thin overburden. Well exposed rocks are only present at the walls of mine pits, bulldozer cuts, old prospects, access roads and in scattered isolated natural outcrops. Only preliminary geologic mapping has been conducted by Globex.
Fluorite is restricted to the southern part of the Paleozoic carbonate rock window in an area measuring about 850 m in length N-S and up to 350 m width. Satellite image analysis indicates that the Carp fluorite occurrences might be controlled by NW-SE trending regional structures and by a crosscutting short N-S fault zone. Fluorite was mined from four open pits:
- South pit (the main pit, measures about 70×50 m and up to about 15 m deep)
- Central pit (85 m long, up to 26 m wide and up to 8 m deep)
- West pit (40 m long, up to 25 m wide and up to 7 m deep)
- North pit 1 (about 75 x 45 m, up to 4 m deep)
- North pit 2 (separate small pit: 30×18 m, up to 5 m deep)
Only remnants of evident fluorspar ore is now exposed in these pits (fluorite cannot always be easily distinguished from carbonate rock), and the geologic mapping gave only a limited amount of information on the original size and shape of the exploited individual orebodies.
In the northwestern project area and in the North pit area intruded several felsic dikes (rhyolite, quartz-latite and rhyodacite) the Paleozoic carbonate rocks. One rhyolite dike and a possible rhyolite stock intruded felsic tuffs and ash-flows 150 m west of North pit 1.
A principal NNW trending fault dipping steeply eastward is located at the west side of the South pit, it controls fluorite vein/manto mineralization. It is indicated that this same fault extends further north crossing into the Central pit, where it controls fluorite mantos and veins. From here this fault appears to bend toward the west and in the West pit the fault strikes almost E-W and dips steeply north. Again the fault controls fluorite vein-, manto-style mineralization and also a possible hydrothermal collapse breccia body.
In the North pit area fluorite mineralization appears as veins and limestone replacement at the contact of felsic dikes (rhyolite, latite, rhyodacite), furthermore along sub-horizontal small thrust faults. In addition in the upper western part of North pit 2 and in a bulldozer cut 200 m further north are exposed brownish colored Fe-oxide stained fine grained metasomatic rocks (protolith perhaps claystone/siltstone or tuff) consisting of silica, clay minerals and extremely fine grained fluorite (cannot be recognized with the loupe).
Fluorite mineralization appears mostly as replacement of carbonate rock, but also as discordant steeply dipping veins/bodies along faults or attached to felsic dikes.
Fluorite is light gray to white, but in other places it is slightly stained by iron oxides exhibiting a pale orange or light yellow-brown color. The ore ranges from compact and firm to slightly friable. Fluorite occurs often as aggregates of massive or saccharoidal crystals less than a millimeter across, and to a lesser extent, as small irregular masses and veinlets of very fine-grained material some of which is crustiform-banded, vuggy, or botryoidal. The manto-ore in the South pit is of pale gray color, and locally exhibits a vuggy texture with small angular cavities derived from dissolved carbonate, it also contains some white clay (montmorillonite?). In the West pit fluorite manto-ore is rhythmically banded (zebra-ore) parallel to the contacts. Fluorite is here pure and massive, appearing as up to several cm-thick dense bands and also as botryoidal crustiform masses in cavities. Botryoidal fluorite in these cavities is partly also of pale-purple color.
Coarse crystalline pure white barite occurs in veins. The thickest, steeply dipping vein is about 1.5 m wide, at least 50 m long, trends ENE and was exploited via a shaft greater 10 m deep.
There exist also indications for carbonate replacement bodies (CRD mineralization type), some might represent sub-vertical mineralized chimney-shaped bodies. These consist of fine granular, partly saccharoidal barite and quartz, chalcedony, minor calcite/dolomite and oxidized Pb-Zn-Cu-Ag ore minerals.
From 25 samples collected in the project area 22 samples contained fluorine above detection limit. From those 14 samples returned very high fluorite grades ranging between 49.83% to 88.15 %. Silica (SiO2) contents of these high-grade fluorite samples ranged between 0.84% and 23.44%, silica content of 9 samples was below 4.0%.
Through the western part of the North pit 1 runs a NNW trending fluorite vein and replacement zone over a length of at least 30 m, in the north it is attached to a rhyolite dike. In the south channel sample C-23 was collected from a surface outcrop over horizontal width of 2.3 m; it returned 80.34% fluorite and 4.27 % SiO2. Sample C-12 was collected at the west side of a white vitrophyric rhyolite dike over a width of 1.2 m. Here clayey bleached, shattered limestone has been replaced by fluorite and opal/chalcedony. The sample returned 73.15% fluorite and 11.05% SiO2.
Sample C-22 assayed 0.387 ppm Au, sample C-24 0.084 ppm Au and sample C-25 0.087 ppm Au. These samples correspond to fluorite replacement of felsic tuff or silty claystone. They exhibit high silica contents (23.44% to 61.38% SiO2) and elevated values of Ti (340 to 743 ppm). High Ti values could indicate a tuff protolith of these metasomatic rocks.
Grab sample C-21 was collected from mineralized float containing barite-Ag-Pb-Zn-Ag mineralization, probably coming from a sub-vertical mineralized carbonate replacement pipe-shaped body (CRD-type deposit). This sample assayed 151.5 ppm Ag, 0.28% Cu, 2.79% Pb and 8.64% Zn.
All fluorite occurrences at the Carp project exhibit textural features also observed in other worldwide carbonate-hosted fluorite deposits typical for Mississippi Valley type deposits (MVT) and for MVT-like fluorite deposits. Fine grain size, acicular & saccharoidal fluorite, botryoidal-crustiform textures, banded zebra-ore and locally intimate association with opal and botryoidal chalcedony indicate very low temperatures of formation. In addition however there can be observed a strong spatial association with Miocene felsic dikes and possibly also with felsic tuffs (replaced by fluorite) in the northern project area.
Geologically Carp fluorite mineralization is astonishingly similar to the world-class Mexican fluorite deposits of the Las Cuevas–Río Verde cluster. Here the locations of very large fluorite ore bodies are controlled by faults and they appear at the contact of carbonate rock to either overlying rhyolite or to rhyolite dikes.
The historic drilling campaign, consisting of 62 core holes, did not encounter significant fluorite mineralization (except near to surface). It was principally done for the follow-up of existing manto-style fluorite ore bodies. Most drill holes were less 50 m deep (only few reached depths of 50 m to maximal 75 m) and all drill holes were vertical. They did not test to greater depth, but especially this drilling campaign did not investigate the probable presence of steeply dipping irregular fluorite ore bodies and the observed fluorite veins. Consequently large or very large fluorite ore bodies could exist, not only near to surface but also at greater depth.
Although the largest manto-ore body at Carp was mined from the South pit, Globex sees the highest exploration potential for the discovery of large or very large fluorite ore bodies in the region around the North pits. Blind ore bodies at depth could be either discovered along the contact of felsic dikes, but also toward the west, for example at or below the west dipping contact carbonate rocks to overlying felsic volcanic rocks. Of special interest is also the felsic dike zone (intruding on surface felsic tuff) 180 m west of North pit 1. At shallow depth should be encountered the favorable carbonate rock underlying the felsic volcanics, a large replacement ore body could be discovered here or at greater depth along the dike contacts.
Sample Collection & Sample Preparation
Globex collected a total of 26 rock samples, 25 samples from the Carp property and one sample (C-26) outside, about 1 km NW of the Carp claim block. Of principal interest was the content of fluorspar (fluorite). For the determination of the fluorite content it was calculated from the fluorine assay results. The normative fluorite content was calculated from values of CaO and F. Furthermore a normative Ca-Mg carbonate content was calculated from CaO, MgO and CO2 (representing the bulk of loss of ignition).
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, split and a 300 g subsample pulverized to >85% -75 micron.
For whole rock analysis + fluorine all powdered subsamples (0.5 g) were fluxed with Li-borate/LiNO3 flux in automatic fusion equipment, fused in a Pt/Au crucible at 1050°C and poured into Pt/Au mold. Loss of ignition (LOI) was determined (corresponds to weight loss of H2O, CO2 and carbon). The borate glass beads were analyzed with Zetium wavelength dispersive X-ray fluorescence (WD-XRF) spectrometer. Note: The analysis of fluorine with XRF is challenging, as the element is characterized by a very weak fluorescence yield, which leads to a low sensitivity. The analysis using borate fusion is also difficult due to the volatility of fluorine at the high flux temperature (1050°C); it is therefore possible that some of the fluorine was lost during the fluxing process, resulting in fluorine assay results that are lower than real rock sample composition. Therefore given fluorine assay results, and from such calculated normative fluorspar (fluorite) percentage, can be considered as minimum values.
Selected samples underwent ICP-OES analysis of a 0.5 g subsample after 5-acid digestion (HNO3, HF, HClO4, HCl and H3BO3) for 51 elements including silver. 5-acid treatment results in near total digest (resistant phases e.g. corundum, ilmenite, rutile are not digested). Gold was analyzed via fire assay of a 30 g subsample and analyzed with ICP-OES. Typical internal standards and checks were completed by AAL during analysis.
History
The Carp mine represents the fourth largest historic producer of fluorspar (fluorite) in the state of Nevada. Currently there is no active fluorspar mining in the United States. In 2023 only minimal fluorspar (calcium fluoride, CaF2) was produced as by-product.
Fluorite was first discovered in 1957 during examination of historic barite prospects. In 1957 Western Mining and Development Company (Wells Cargo Inc.) purchased and staked 22 contiguous claims in the area. Production of fluorspar from four open pits initiated in March 1958. Total estimated production until 1971 was 44,900 t @ 69% CaF2. Almost all of this production was attained in 1958-1959 and 1968-1971, but shipments from stockpiles were made through much of the 1960’s. The largest exploited fluorspar ore body (manto) was mined from the southern open pit. Apparently it had a diameter of about 30 m, and reportedly had a thickness of about 5 m. Fluorite was shipped/sold as metallurgical grade (“metspar”) without prior concentration to Kaiser Steel Corporation. Silica content was very low (no or very low penalties). From mid-1968 to 1972 the mine was operated by several groups of lessees, and in the early 1970’s extensive exploration was done on the property by Allied Chemical Co.
Allied Chemical Co. built numerous access roads and drill pads, excavated bulldozer cuts and conducted mapping, a gravity and magnetic survey and also drilled 62 vertical core (?) holes totalling about 2182 m. From these drill holes 28 holes reached depths of less 25 m, 22 holes were between 25 and 50 m deep and 12 holes ranged in depth between 50 to 75 m. Only 8 holes intersected near-surface (all at less 10 m depth) fluorite manto-style ore with grades ranging between 10% and 54.8% CaF2.