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2017 BC Government Geological Survey Assessment Report 37398 in the Slocan Graphite region
https://aris.empr.gov.bc.ca/ARISReports/37398.PDF
(Extract from Page 18 to 20)
Graphite
The BCGS Mineral Deposit Model for Crystalline Flake Graphite (PO4: Simandl and Kenan, 1996) is interpreted to “... describe a geological setting ... identical to the Tedesco graphite deposits. Although in the early stages of exploration, geological, assay, and geophysical data indicate significant potential to identify an economic deposit. The host rocks (Units 2, 3) form conspicuous rusty graphitic gneiss with interbedded 5-10 metre thick graphitic marble layers. Average thickness of the mineralized section is unknown at this time, but the pattern of outcrops and float indicate that it may be 50 metres thick. Graphitic outcrops have been found for more than 2 kilometres across the grid, and a broad area of float occurrences of identical material can be traced on strike for a significant distance.
Seven assay samples of altered graphitic surface material were analysed using the CANMET recommended procedures. Assays varied up to 3.5% Carbon / Graphite, low-grade but with large crystalline graphite flakes. The geophysical surveys tend to support the overall trend and dimensions as given. Fraser-Filtered VLF-EM data consistently shows anomalous conductive zones and magnetometer anomalies associated with the graphitic outcrops and the hanging wall of the deposit. Pyrite, pyrrhotite, chalcopyrite, and sphalerite are known to occur within this sequence as stratiform layers or disseminations, and are the probable cause of several spot high geophysical readings.
Petrographic examination of samples Jgr-5 and Jgr-8 shows these rocks to be pyroxenebearing quartz monzonite or monzodiorite gneiss composed of calcic plagioclase (labradorite), clinopyroxene (diopside), K-feldspar, quartz, and phlogopite or muscovite, with accessory pyrrhotite, graphite, sphene, apatite, pyrite, and rare sphalerite and chalcopyrite: carbonate is virtually absent. Graphite is slightly more abundant at location Jgr-8 than Jgr-5 (Leitch, 2000).
The Tedesco graphite deposits are fortunate to have a large nearby graphite deposit under development at IMP mining’s (now owned by Eagle Graphite Corp.) Black Crystal graphite deposit on Hoder Creek. The IMP graphite test mill is located a few kilometres west of the property boundary. Regionally, the sequence of rocks present on the Tedesco grid has been correlated with the Rinda Ridge composite unit of Schaubs and Carr (1998) which hosts the inferred 88 million tonne Black Crystal flake graphite deposit, grading 4- 5% crystal graphite. Given the economic potential of the large Hoder Creek graphite deposit and the correlative geology, the Tedesco graphite occurrences are an important exploration target. …” (AR 26537). From May 16-29, 2012, a two person crew managed by John Demes completed prospecting for graphite on the southwest flank of Perry Ridge in an area covered by the current EPL tenure (AR33540 – Appendix C). Demes reported finding graphite-bearing float and outcrops all the way from about 850m elevation to about 1440m. A total of 20 samples were collected and analyzed for total carbon content (Figure 4). All rocks were “gneissic” containing 2-5% graphite. Outcrops strike east approximately AZ 270 with dips 64-88o (direction not stated).
Tedesco Garnet
A flat-lying garnetiferous pegmatite sill (Unit 4), varying from 30 to 50 centimetres in thickness, is exposed for 30 metres along a logging road on Tedesco grid (AR 33540). Handtrenching exposed at least four metres in width ... and the sill remains open in all directions. The garnetiferous sill is adjacent to a graphitic schist outcrop and a feldspar pegmatite sill, but the stratigraphic relationships are unclear due to shallow overburden cover.
Garnet occurs as irregularly distributed single crystals up to 10 centimetres in diameter and in crystalline masses up to 30 centimetres in width. The variety of garnet is almandine- pyrope of unknown proportions and the colour is described as an intense fiery red. The average weight content of garnet to host rock is approximately 10%, based on the recent bulk sample results. The large garnet crystals occasionally display a regrowth of garnet in a parasitic internal crystal of the same colour, and which is often more transparent than the host garnet.
Sample TGAR ... consists of coarse red garnet enclosed or encased in green biotite, in a matrix of quartz diorite (albite-oligoclase, quartz, K-feldspar). Fractures in this garnet are widely spaced (about l mm apart on average, with areas of lower density in some places, especially towards the core of the crystal). Inclusions of quartz, biotite, and plagioclase are common, but are mainly restricted to the margins of the crystals (Leitch, 2000). Minor amounts of graphite, pyrite and chalcopyrite are also locally present in the pegmatite host rock.
Aquamarine
Aquamarine beryl crystals of gem grade were discovered on the greater Blu Starr property in 1995. Aqua crystals are a light green-blue colour and occur within a quartz-feldspar-muscovitetourmaline pegmatite dike with miarolitic cavities. The main occurrence (Peg 1; AR 33540) and other lesser occurrences are located near the southwest corner of the property on the Slocan 2 claim. The sinuous and irregular dike is exposed for about 10 metres along strike and 2 metres in width, and is hosted by quartz-feldspar-biotite gneiss.
Approximately 20-25 aquamarine crystals were extracted from the Peg 1 pegmatite dike in 1996. The crystals can reach 5 centimetres long by 1.5 centimetres in width (100-125 2017 carats), and contain clear areas that would produce 0.5 carat gemstones (Gauthier and Dixon, 1996). Smokey and clear quartz, schorl tourmaline, and garnet are also found in Peg 1. The Peg 1 dike outcrops approximately 100 metres uphill from an old logging road and could be explored with non-explosive extraction methods such as compressor and jackhammer.
Quartz-tourmaline pegmatite dikes are of relatively common occurrence throughout the property often associated with 110° azimuth-trending, narrow sub-vertical zones of folding and fracturing. Non-gem aquamarine beryl crystals up to 4 centimetres by 5 centimetres in size have been found in large pegmatite float blocks located on the talus slope near the south iolite showing (I2) on the Blu Starr / Iolite grid.
Several aquamarine-bearing dikes occur on the Blu Starr Property proximal to the BQ claims on the ridge between Cowie and Airy creeks. The BQ claims are entirely contained within the Blu Starr Property, and host blue-green aquamarine beryl, almandine-pyrope garnet and smoky quartz in miarolitic cavities in a tourmaline pegmatite dike. The largest aquamarine crystal discovered to date weighs 47.2 grams (236 carats), and the largest faceted aqua weighs 5.26
carats. Garnet from this deposit has also been faceted, and the largest stone cut to date weighs 4.04 carats.
Emerald is the grass-green variety of beryl, and has not been found yet in the Slocan area. Many of the known deposits of gem emerald around the world occur within very similar geological environments to the Valhalla complex. A conceptual model of a potential emerald deposit in the Silocan Valley requires proximity to major faulting and shearing, berylbearing pegmatites, and a geochemical source of chromium or vanadium such as ultrabasic rocks to create the emerald colour in the beryl crystals. This geological environment would also support the deposition of chrysoberyl. One of the varieties of chrysoberyl is better known as alexandrite, a rare and very expensive gemstone.
https://aris.empr.gov.bc.ca/ARISReports/37398.PDF
(Extract from Page 18 to 20)
Graphite
The BCGS Mineral Deposit Model for Crystalline Flake Graphite (PO4: Simandl and Kenan, 1996) is interpreted to “... describe a geological setting ... identical to the Tedesco graphite deposits. Although in the early stages of exploration, geological, assay, and geophysical data indicate significant potential to identify an economic deposit. The host rocks (Units 2, 3) form conspicuous rusty graphitic gneiss with interbedded 5-10 metre thick graphitic marble layers. Average thickness of the mineralized section is unknown at this time, but the pattern of outcrops and float indicate that it may be 50 metres thick. Graphitic outcrops have been found for more than 2 kilometres across the grid, and a broad area of float occurrences of identical material can be traced on strike for a significant distance.
Seven assay samples of altered graphitic surface material were analysed using the CANMET recommended procedures. Assays varied up to 3.5% Carbon / Graphite, low-grade but with large crystalline graphite flakes. The geophysical surveys tend to support the overall trend and dimensions as given. Fraser-Filtered VLF-EM data consistently shows anomalous conductive zones and magnetometer anomalies associated with the graphitic outcrops and the hanging wall of the deposit. Pyrite, pyrrhotite, chalcopyrite, and sphalerite are known to occur within this sequence as stratiform layers or disseminations, and are the probable cause of several spot high geophysical readings.
Petrographic examination of samples Jgr-5 and Jgr-8 shows these rocks to be pyroxenebearing quartz monzonite or monzodiorite gneiss composed of calcic plagioclase (labradorite), clinopyroxene (diopside), K-feldspar, quartz, and phlogopite or muscovite, with accessory pyrrhotite, graphite, sphene, apatite, pyrite, and rare sphalerite and chalcopyrite: carbonate is virtually absent. Graphite is slightly more abundant at location Jgr-8 than Jgr-5 (Leitch, 2000).
The Tedesco graphite deposits are fortunate to have a large nearby graphite deposit under development at IMP mining’s (now owned by Eagle Graphite Corp.) Black Crystal graphite deposit on Hoder Creek. The IMP graphite test mill is located a few kilometres west of the property boundary. Regionally, the sequence of rocks present on the Tedesco grid has been correlated with the Rinda Ridge composite unit of Schaubs and Carr (1998) which hosts the inferred 88 million tonne Black Crystal flake graphite deposit, grading 4- 5% crystal graphite. Given the economic potential of the large Hoder Creek graphite deposit and the correlative geology, the Tedesco graphite occurrences are an important exploration target. …” (AR 26537). From May 16-29, 2012, a two person crew managed by John Demes completed prospecting for graphite on the southwest flank of Perry Ridge in an area covered by the current EPL tenure (AR33540 – Appendix C). Demes reported finding graphite-bearing float and outcrops all the way from about 850m elevation to about 1440m. A total of 20 samples were collected and analyzed for total carbon content (Figure 4). All rocks were “gneissic” containing 2-5% graphite. Outcrops strike east approximately AZ 270 with dips 64-88o (direction not stated).
Tedesco Garnet
A flat-lying garnetiferous pegmatite sill (Unit 4), varying from 30 to 50 centimetres in thickness, is exposed for 30 metres along a logging road on Tedesco grid (AR 33540). Handtrenching exposed at least four metres in width ... and the sill remains open in all directions. The garnetiferous sill is adjacent to a graphitic schist outcrop and a feldspar pegmatite sill, but the stratigraphic relationships are unclear due to shallow overburden cover.
Garnet occurs as irregularly distributed single crystals up to 10 centimetres in diameter and in crystalline masses up to 30 centimetres in width. The variety of garnet is almandine- pyrope of unknown proportions and the colour is described as an intense fiery red. The average weight content of garnet to host rock is approximately 10%, based on the recent bulk sample results. The large garnet crystals occasionally display a regrowth of garnet in a parasitic internal crystal of the same colour, and which is often more transparent than the host garnet.
Sample TGAR ... consists of coarse red garnet enclosed or encased in green biotite, in a matrix of quartz diorite (albite-oligoclase, quartz, K-feldspar). Fractures in this garnet are widely spaced (about l mm apart on average, with areas of lower density in some places, especially towards the core of the crystal). Inclusions of quartz, biotite, and plagioclase are common, but are mainly restricted to the margins of the crystals (Leitch, 2000). Minor amounts of graphite, pyrite and chalcopyrite are also locally present in the pegmatite host rock.
Aquamarine
Aquamarine beryl crystals of gem grade were discovered on the greater Blu Starr property in 1995. Aqua crystals are a light green-blue colour and occur within a quartz-feldspar-muscovitetourmaline pegmatite dike with miarolitic cavities. The main occurrence (Peg 1; AR 33540) and other lesser occurrences are located near the southwest corner of the property on the Slocan 2 claim. The sinuous and irregular dike is exposed for about 10 metres along strike and 2 metres in width, and is hosted by quartz-feldspar-biotite gneiss.
Approximately 20-25 aquamarine crystals were extracted from the Peg 1 pegmatite dike in 1996. The crystals can reach 5 centimetres long by 1.5 centimetres in width (100-125 2017 carats), and contain clear areas that would produce 0.5 carat gemstones (Gauthier and Dixon, 1996). Smokey and clear quartz, schorl tourmaline, and garnet are also found in Peg 1. The Peg 1 dike outcrops approximately 100 metres uphill from an old logging road and could be explored with non-explosive extraction methods such as compressor and jackhammer.
Quartz-tourmaline pegmatite dikes are of relatively common occurrence throughout the property often associated with 110° azimuth-trending, narrow sub-vertical zones of folding and fracturing. Non-gem aquamarine beryl crystals up to 4 centimetres by 5 centimetres in size have been found in large pegmatite float blocks located on the talus slope near the south iolite showing (I2) on the Blu Starr / Iolite grid.
Several aquamarine-bearing dikes occur on the Blu Starr Property proximal to the BQ claims on the ridge between Cowie and Airy creeks. The BQ claims are entirely contained within the Blu Starr Property, and host blue-green aquamarine beryl, almandine-pyrope garnet and smoky quartz in miarolitic cavities in a tourmaline pegmatite dike. The largest aquamarine crystal discovered to date weighs 47.2 grams (236 carats), and the largest faceted aqua weighs 5.26
carats. Garnet from this deposit has also been faceted, and the largest stone cut to date weighs 4.04 carats.
Emerald is the grass-green variety of beryl, and has not been found yet in the Slocan area. Many of the known deposits of gem emerald around the world occur within very similar geological environments to the Valhalla complex. A conceptual model of a potential emerald deposit in the Silocan Valley requires proximity to major faulting and shearing, berylbearing pegmatites, and a geochemical source of chromium or vanadium such as ultrabasic rocks to create the emerald colour in the beryl crystals. This geological environment would also support the deposition of chrysoberyl. One of the varieties of chrysoberyl is better known as alexandrite, a rare and very expensive gemstone.
