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File Created: 24-Jul-85 by BC Geological Survey (BCGS)
Last Edit:  27-Nov-14 by Laura deGroot(LDG)

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NMI 082N3 Pb1
Name CROWN POINT, MCMURDO CREEK, A, B, RIALTO, BLUFF, C, GOLD, REGINA (L.11631), NEW CROWN POINT (L.11630), PRESIDENT (L.6650) Mining Division Golden
BCGS Map 082N005
Status Past Producer NTS Map 082N03E
Latitude 51º 02' 18" N UTM 11 (NAD 83)
Longitude 117º 08' 46" W Northing 5654098
Easting 489756
Commodities Lead, Silver, Zinc, Gold Deposit Types I05 : Polymetallic veins Ag-Pb-Zn+/-Au
J01 : Polymetallic manto Ag-Pb-Zn
E14 : Sedimentary exhalative Zn-Pb-Ag
Tectonic Belt Omineca Terrane Ancestral North America
Capsule Geology

The Crown Point property is located between the 1828 to 2438 metre elevation at the head of McMurdo Creek, a northeasterly flowing tributary of the Spillimacheen River, about 30 kilometres south-southwest of Golden. Early work on the property consisted of surface stripping, adits and raises carried out at five locations. The most extensive are at the A showing at the 2069-metre elevation. Located northwesterly from the A showing are the Rialto, B, Bluff and C showings. The C workings are on the northwest side of a small tributary of McMurdo Creek about 1.2 kilometres northwest of the A workings and 91 metres higher. A series of veins known as the Gold showing are located about 800 metres southeast of the A workings at an elevation of about 2286 metres. The B showing lies 548 metres northwest of the A showing; the Bluff showing lies west of the B showing. The Rialto showing is located 304 metres northwest of the A showing.

By 1936, the A workings comprised 4 adits and 5 raises totalling 762 metres of underground development and are located on the Regina (Lot 11631), New Crown Point (Lot 11630) and President (Lot 6650) claims. The B workings consist of a 7-metre adit and opencuts; the Bluff workings, 2 short adits; the C workings, about 97 metres of drifts and crosscuts in 3 adits; and the Rialto, an adit.

Hostrocks on the property consist of schists, quartzites, grits and limestone of the Hadrynian Horsethief Creek Group. They are folded into a broad anticline with, apart from local anomalies, moderate to gently dipping limbs. The crest of this anticline, one of a series of open rolls, can be seen several kilometres to the northwest and also to the southeast, across "Bobbie Burns Basin" where the Robert E. Burns (082N 008) and Flying Dutchman (082N 006) occurrences are located. The dominant cleavage is nearly vertical, axial to the anticline.

The most important mineralization is at the A showing and is hosted in limestone on the southwest limb of the main anticline. The limestone and enclosing slate are complexly dragfolded, crumpled and faulted. About 7 to 12 metres of limestone and limy strata are involved in a series of asymmetrical dragfolds that are cut by faults of relatively small displacement. An ore zone, only the fringes of which are exposed in an adit, consists of stringers, pods and lenses of galena and lesser sphalerite, pyrite and siderite; the sulphides vein and replace the limestone. In 1948, the A zone was established as being 103 metres long, 15 metres wide and 7 metres thick. The same zone has, according to early reports, about 35,857 tonnes of indicated ore grading 117.2 grams per tonne silver, 6.24 per cent lead and 0.18 per cent zinc (Northern Miner - August 20, 1970).

The C showing, 1.2 kilometres north of the A showing, consists of an irregular quartz vein in quartzite and schist. The C vein is related to an irregular, sharp crumple and is exposed for a length of about 22 metres on a steep slope. The vein is from several centimetres to 3 metres wide and contains pods and lenses of galena-sphalerite-pyrite. At the upper end of a stripped area the vein splits, and the branches appear to be very irregular. A sample of selected mixed sulphides assayed 12.3 grams per tonne gold, 377 grams per tonne silver, 23.3 per cent lead and 0.2 per cent zinc (Minister of Mines Annual Report 1936, page E37).

Just beneath a small glacier, several quartz veins, known as the Gold showings, occur in an area about 37 square metres. These veins are on the crest of the anticline and for the most part are axial to it, although some have a northerly or easterly strike. The veins are from a few centimetres to as much as 3 metres wide and are very sparsely mineralized with pyrite. The veins are hosted in quartzite, which is about 30 metres thick; most of the veins pinch out in underlying schist. The veins may represent fracture fillings in the shattered, more competent rock in the anticlinal crest.

The B showing lies 548 metres northwest of the A showing and comprises a quartz vein hosted in flat-lying grey schist with some local limestone evident. The vein varies from 15 to 91 centimetres wide, and splits into two branches to the east. Mineralization consists of galena and pyrite.

The Bluff showing lies west of the B showing and is underlain by schist and limestone in fault contact. The limestone is impregnated with disseminated grains of galena and sphalerite. Some of the better disseminated mineralization assayed 34.2 grams per tonne silver, 2.5 per cent lead and 9.6 per cent zinc (Minister of Mines Annual Report 1936, page E37).

The Rialto showing is located 304 metres northwest of the A showing. An outcrop of numerous, narrow, pyritic quartz stringers aggregating 7.6 metres in width cut across the schistosity of the host chlorite schist. A grab sample from a 4.5-tonne dump of sorted pyritic quartz at the mouth of the Rialto tunnel assayed 5.4 grams per tonne gold and 13.7 grams per tonne silver (Minister of Mines Annual Report 1932, page A160).

Bibliography
EMPR AR 1890-364; 1895-673; 1898-1052-1054; 1899-594; 1909-K272;
1928-C275; 1929-C285,C290,C291; 1930-A232-A234; *1932-A160,A161;
*1936-E25-E28,E33-E37; 1947-A177; 1948-A152; 1949-A204,A205
EMPR BC METAL MM00554
EMPR FIELDWORK 2000, pp. 231-252
EMPR PF (82N General File - Prospector's map, 1937; Surface geology
map of a portion of the McMurdo Creek property; Plan of the
surface geology of the A workings; Prospectors Report 1999-6 by
Barbara Welsh)
EMR MIN BULL MR 223, B.C. 83
EMR MP CORPFILE (Beverly Mines, Limited; New Chemcrude Resources
Ltd.)
GSC MAP 4-1961; 43-1962
GSC OF 481
GSC P 62-32
CANMET IR 2575 (1949)
N MINER *Aug.20, 1970

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