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File Created: 24-Jul-1985 by BC Geological Survey (BCGS)
Last Edit:  28-Feb-2008 by Karl A. Flower (KAF)

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NMI 082E2 Au2
BCGS Map 082E017
Status Past Producer NTS Map 082E02E
Latitude 049º 09' 39'' UTM 11 (NAD 83)
Longitude 118º 36' 47'' Northing 5446588
Easting 382400
Commodities Silver, Gold, Lead, Copper, Zinc, Cadmium, Silica Deposit Types H08 : Alkalic intrusion-associated Au
I05 : Polymetallic veins Ag-Pb-Zn+/-Au
Tectonic Belt Omineca Terrane Slide Mountain, Plutonic Rocks
Capsule Geology

The Jewel (Lot 850) claim and four additional Crown granted claims, including Denero Grande (Lot 851), Enterprise (Lot 1022), Anchor (Lot 1021) and Ethiopia (Lot 932) (082ESE151), comprise what is known as the Dentonia property. This is centred approximately 10.5 kilometres east of Jewel Lake on the west slope of Mount Pelly. Access is by the Jewel Lake road which joins Highway 3, a few kilometres north of Greenwood.

Production in the period 1900 to 1985 from this property totals 124,644 tonnes of ore having 1348 kilograms of gold, 8055 kilograms of silver, 168 tonnes of lead, 4 tonnes of zinc, 6.5 tonnes of copper and 57 kilograms of cadmium. Most of this ore was mined from the Jewel and Enterprise claims in 1912 to 1916 and 1934 to 1943. Minor production was realized from the Enterprise and Anchor claims in 1947 and 1948, from the Denero Grande in 1974 and 1975, and from the Jewel in 1984 and 1985.

The Dentonia mine is aligned in a northerly direction on a 1200-metre long easterly dipping vein. Entrance to the old underground workings is by two adits and four inclined shafts, the most important of which are the Jewel shaft and the Enterprise adit crosscut. The Jewel shaft, on the south part of the Jewel claim, connects five working levels and serviced the main ore body to a depth of about 120 metres. The Enterprise tunnel, at the elevation of about 1200 metres, was driven easterly from Jewel Lake to intercept the base of the Enterprise ore body at the boundary of the Jewel and Enterprise claims.

A mill was erected in 1909 and operated until the property was abandoned in 1914. A renewed period of mining prompted construction of a second mill which operated from 1933 to 1936.

The continuation of the Dentonia vein on the Denero Grande claim was actively explored in 1973. This led to the sinking of a vertical shaft to a depth of 90 metres. By April 1975, over 300 metres of drifting and raising on the vein had been done and the vein was located by underground drilling to the north, south and below the new workings. Five stoping areas had been opened up and over 2000 tons of ore had been mined. Additional shaft sinking and drifting has been completed since 1980.

The claims are underlain by greenstones, pelitic schists and chert of the Upper Paleozoic Knob Hill Group; these are intruded by the Jurassic/Cretaceous Wallace Creek granodiorite. The Dentonia quartz vein cuts northeasterly (020) across the strike of these formations, averaging about one metre in width. Mineralization consists mostly of disseminations and small pockets of sulphides in quartz. The ore minerals are mostly pyrite and galena with minor amounts of sphalerite, chalcopyrite, tellurides and some native gold.

The Dentonia quartz vein structure is explosed over a length of approximately 1828 metres and can be traced from a point 457 metres north of the Ethiopia (Lot 932) adit (082ESE151), and south a distance of 1371 metres to the extremity of the Denero Grande workings. Essentially it follows a fracture zone which strikes south across the trend of the metamorphosed rocks. The fracture zone dips east to southeast at 30 to 60 degrees with variable strike, widths and amount of shearing.

Previous development work centred on two areas of the vein referred to as the Jewel and Enterprise sections with a combined length of 731 metres. The Jewel section comprises slightly less than half of the total development and extended from the north boundary of the Denero Grande claim to 158 metres north of the Jewel shaft. Much of the ore was taken from a thickened part of the vein where it traverses the contact between granodiorite and schistose volcanic rocks. The Enterprise section is 425 metres to the north of the Jewel shaft with the main orebody lying between the White and Enterprise shafts. The orebody had a length of more than 122 metres averaging 1.9 metres wide and ranging to 4.8 metres wide. The Rowe ore shoot, located midway between the Jewel and the main Enterprise workings, was comparatively small and high grade. A pulaskite dyke followed, displaced and eventually cut the vein. The Anchor ore shoot, 150 metres north of the Enterprise orebody, was small and detached from the Enterprise.

Locally the metamorphosed volcanic and sedimentary rocks are not always distinguishable, both being fine-grained and medium or dark coloured with primary structures such as bedding and flow banding being confused with foliation or gneissosity. Generally the sedimentary rocks are brittle and quartz-rich, however, compositions vary and some biotitic varieties have the same competence as the amphibole-rich volcanic rocks. The bulk of the northwest striking and steeply northeast dipping sedimentary rocks are located in the north part of the property near the Anchor workings. They are locally called quartzites but few are true quartzites and more appropriate terms would be quartz wacke or lithic wacke. The volcanic rocks are most abundant on the Jewel claim. The massive character of the volcanic rocks is due to a combination of intense regional metamorphism and primary structures. Field and petrographic data indicate that at least some of the original rock formed as a result of massive accumulations of lava flows and pillow lava. Crosscutting feeder dykes and sills are significant and contribute to the massive aspect of the volcanic rocks. The metamorphosed schistose volcanic rocks are compositionally basalts.

Igneous intrusions in the Jewel mine area include a large Lower Cretaceous granodiorite pluton and a host of younger pulaskite and lamprophyre dykes. The granodiorite returned a potassium-argon age date of 128 Ma +/- 5 Ma, and is correlative with Nelson Intrusions. The granodiorite is a homogeneous medium-grained grey body intruding the metavolcanic rocks along a northwest trending contact in the southwest part of the camp. Alteration is minor with some replacement of amphibole by epidote. The intrusive has produced little effect in both the metavolcanic and metasedimentary rocks. Granodiorite dykes occur and are compositionally similar to the main granodiorite body and are probably offshoots from it. Pulaskite dykes are numerically most important. Several types are evident including both quartz-bearing and under saturated types. The largest pulaskite dyke is exposed between the Enterprise portal and the Jewel shaft. A second smaller dyke is located midway between the Enterprise portal and Enterprise shaft. Post-vein lamprophyre dykes as well as the pulaskite dykes are of probable Lower Tertiary age and cut all other major geological units on the property.

The Dentonia vein ranges widely in attitude with strikes varying from 000 to 050 degrees averaging about 020 degrees and dipping between 30 and 60 degrees southeast. As the dip increases the vein generally narrows, merging with steeply dipping joints and shears also striking about 020 degrees, and a set of strong crossjoints at roughly 045 degrees and vertical dips developed at right angles to the strike and foliation of the local country rocks. The age of the Dentonia vein is bracketed by the granodiorite which locally hosts the vein, and by crosscutting pulaskite and lamprophyre dykes. The dykes are correlated with petrographically similar Tertiary lavas at the summit of Mount Pelly and with volcanic rocks which occur to the west near Midway, dated at 49 Ma +/- 2 Ma. In general, the Dentonia vein cuts granodiorite in the south, metasedimentary rocks in the north, and intervening metavolcanic rocks. Vein widths vary from an average of 0.9 metre to a maximum of 4.8 metres.

Mineralization within the quartz vein includes mostly pyrite, galena and chalcopyrite with sphalerite, tellurides, native gold and possible arsenopyrite. The minerals are not especially abundant, occurring mainly as grey streaks and fine disseminations or as small pockets and lenses. At a number of places granodiorite dykes interrupt the vein and locally cut the vein off. Splays and screens of country rock as well as post-vein pulaskite or lamprophyre dykes cause considerable dilution in some areas. There is generally very little alteration or silicification of the wallrock, but minor shattered zones or minute parallel cracks contain stringer-type mineralization.

Ore controls are attributed to several factors, the most important of which are deflections in the vein attitude and the response of the main fissure zone to sudden changes in the composition of the host rocks. Both of these features are present in the Jewel ore body. Here the vein is enlarged and somewhat refracted at the intersection of brittle granodiorite and the less competent schistose volcanic rocks. A major deflection in the strike of the vein is not so apparent in the case of the Anchor shoot at the greenstone/metaquartzite contact, although the vein is generally less steeply inclined. The great width of quartz in the main part of the Enterprise section appears to be solely the result of a major variation in the direction of the fissure zone caused by stresses acting on rather homogeneous greenstone.

The origin of the vein structure is the result of regional stresses. Apparently, tensional gash fractures developed attendant to north-trending shears in response to compressional stress from the southwest, allowing the influx of quartz. The amount of movement was small and the direction is believed to have been largely horizontal. The host rocks are not thought to have offered any special opportunity for chemical reaction with the ore bearing solutions, however, there was a tendency for the greenstone to split and fray under stress, the walls of the vein and septa showing some evidence of replacement. The age of the Dentonia vein is bracketed by the Wallace Creek granodiorite, which locally hosts the vein, and crosscutting young dikes. A sample of the granodiorite from the Denero Grande shaft area returned an early Cretaceous potassium/argon date of 128 +/- 5 Ma (Church, 1986). The numerous feldspar porphyry and pulaskite dikes found, cutting across the mine workings, are clearly feeders to the Marron lavas of the Penticton Group (Eocene).

The continuation of the Dentonia vein 183 metres south of the Jewel workings to the Denero Grande claim has resulted in the Denero Grande shaft being sunk to a depth of 155 metres followed by extensive underground development. Silica smelter credits have been received from some shipments of ore.

Both measured (semi-proven) and indicated (probable) reserves at Dentonia were 90,710 tonnes grading 68.56 grams per tonne silver and 10.96 grams per tonne gold (Northern Miner - May 29, 1975).

EMPR AR 1896-582; 1897-588,589; 1898-1124,1194,1195; 1899-604,764,
765,817; 1900-878; 1901-1056; 1902-H176,H179,H180; 1903-H166,H171;
1905-J183; 1906-H159; 1909-K131,K132; 1910-K120; 1912-K167,K323;
*1913-K146-K149,K163,K421; 1914-K334,K399,K511; 1915-K201,K446;
1916-K21,K518; 1917-F20; 1921-G184; 1922-N176,N177; 1926-A215;
1927-G237; 1928-C250; 1930-A222,A223; 1931-A125; 1932-A130; *1933-
A158-A160; 1934-D5; 1935-A25,A30,D10,G52; 1936-D25,D56; 1937-A29,
A36,A41,D32; 1938-A27,A34,D37; 1939-A29,A36,A77; 1940-A17,A63;
1941-A18,A24,A25,A61; 1942-A20,A26,A59; 1943-A37,A63; 1944-A33;
1945-A95; 1946-A28,A135; 1947-A37,A155,A276; 1948-A37,A127,
A192-A193; 1974-A117,A119; 1975-A91,A93
EMPR BULL 1 (1932), pp. 84,85; 20, Part II, pp. 11-12
EMPR ENG INSP (Mine plans; Geology)
EMPR EXPL 1975-E15; 1980-21,22; 1984-7
EMPR FIELDWORK 1974, pp. 56-58; 1986, p. 19
EMPR GEM 1973-41; *1974-39-51
EMPR INDEX 3-194,201
EMPR INF CIRC 1985-1, pp. 22,42; 1986-1, pp. 41,45; 1988-1, pp. 20,59
EMPR IR 1986-1, p. 110
EMPR MIN STATS 1985, p. 48
EMPR MINING 1975-1980, Vol. I, pp. 8,9
EMPR MR MAP 6 (1932)
EMPR OF 1990-25; 1998-10
EMPR P 1986-2, pp. 36-37
EMPR PF (Starr, C.C. (1928-06-12): Report of Preliminary Examinations of the Jewel - Etheopea Group; Starr, C.C. (1928-06-12): Blueprint Map - Jewel and Dentonia Claims; Starr, C.C. (1928-06-12): Sketch Map of Jewel-Etheopea Surface; Starr, C.C. (1928-06-12): Sketch Map - Burns; Starr, C.C. (1928-06-12): Handwritten Note; *Hedley, M.S. (1941): Geology of Jewel Lake Camp and of the Dentonia Mine; Colt Resources Ltd. (1973-06-27): Progress Report - Drilling and Assay Results on Dentonia Mine; Church, B.N. and Winsby, J. (1974): Dentonia Mine, Jewel Lake Area; Dentonia Resources Ltd. (1983-05-01): Plan Map of Jewel Property; Dentonia Resources Limited (1983-06-01): Management Optimistic)
EMR MIN BULL MR 166, p. 14
EMR MP CORPFILE (Dentonia Mines Ltd.; Colt Res. Ltd.; Dentonia Res.
EMR MP RESFILE (Dentonia Mines Ltd.)
GSC MAP 828; 6-1957; 10-1967; 1500A; 1736A
GSC OF 481; 637; 1969
GSC P 67-42, 79-29
GSC SUM RPT 1901, p. 65; 1902, p. 127
CANMET IR 1933-743, pp. 101-106; 1935-763, p. 226
CIM Reporter Oct. 30, 1981
CMJ Dec.5, 1973
GCNL #100(May 23), #179(Sept.12),#186(Sept.20), #214(Oct.31), 1973;
Feb.3, #214(Nov.4), 1974; Nov.28, 1975; June 16, #134, 1981; #227,
1982; #8,#14,#16,#34,#47,#68,#72,#78,#93, 1983
IPDM May/Apr 1983
N MINER May 3, 1973; Mar.28, 1974; May 29, 1975; May 28, 1981;
Jan.27,Apr.14,July 7, 1983
NAGMIN June 1, 1983
W MINER Sept. 1975
Placer Dome File