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Ontario Geological Survey
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MDI42E13SE00011
| Record Name(s) | Jacobus Prospect - 9999, Chesterville Mines - 9999, Jacobus - 1980 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Developed Prospect With Reported Reserves or Resources |
| Date Created | 1980-Mar-25 |
| Date Last Modified | 2022-Jun-14 |
| Created By | |
| Revised By |
Primary Commodities: Copper, Nickel
Township or Area: Elmhirst
Latitude: 49° 49' 37.53" Longitude: -87° 44' 6.01"
UTM Zone: 16 Easting: 447135.958 Northing: 5519665.48 UTM Datum: NAD83
Resident Geologist District: Thunder Bay North
NTS Grid: 42E13SE, 42E13SW
Point Location Description: Trenches and diamond-drill holes.
Location Method: Data Compilation
Access Description: The property is located in northwestern Elmhirst Township, 56 km west of Geraldton and 31 km northeast of Beardmore. The prospect is located approximately 1.6 km east and 0.8 km south of the township boundaries. Travel approximately 19.6 km north of Nezah (10.1 km west of Jellico) on secondary Highway 801, north on a lumber road for about 7.2 km and 0.8 km on foot.
1947: Properties staked by Christiansen Prospectors Syndicate. Four trenches dug. 1948: Optioned by International Nickel Co. of Canada Ltd., who drilled 9 deep holes then dropped the option. 1957: Jacobus Mining Corporation Ltd. conducted geological and geophysical (mag and EM) surveys. 46 holes were diamond-drilled in the area of the original trenches. 1968: Chesterville Mines Ltd. drilled 9 holes to earn a 75% interest in the Jacobus properties. 1969: Chesterville Mines Ltd. conducted mag, EM and geological surveys. Geochemical work and sampling of existing trenches was also completed. 1971: Chesterville Mines Ltd. conducted an IP survey and a 6-hole drill program. 1972: Chesterville drilled 3 holes. 1976: Jacobus Mining Corp. Ltd. and Chesterville Mines Ltd. both had their Ontario Charters cancelled. 1979: The lease was discharged. As of 1986, the ground was no longer leased, but was not available for staking.
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| 63.947 | 42E13SE0040 | 42E13SE0040 |
Province: Superior
Geological Age: Archean
Dec 07, 2005 (B Nelson) - Four of the southern claims in the block are underlain by the Pinel Creek intrusion, a body of gabbroic rock. The remaining claims to the north are underlain by felsic to intermediate metavolcanics, and parts of the eastern-most claims occur withing the Elmhirst Lake Stock. The upper contact of the intrusion is found to be sharp in drill core. From the drilling it is estimated that the body forms a sill striking about N70 degrees E, and dipping between 45 degrees and 60 degrees to the north, and has a thickness of at least 180 m. Faust's study (1973), suggests that the body is a differentiated layered mafic--ultramafic sill. The sulphide mineralogy constitutes between 4% and 6% of the gabbro within the mineralized zone. Drilling has shown that the zone varies between 6 and 45 m, averaging about 12 m in diameter and extending for at least 300 m in a N60 degrees W direction. The sulphide mineralization is disseminated interstitially within melanocratic gabbro which contains about 90% ferromagnesian minerals. Non-mineralized gabbro consists of approximately equal amounts of plagioclase and ferromagnesian minerals. No sulphides occurred in the quartz-rich leucocratic gabbro. According to Faust (1973), all of the sulphides are embayed or replaced by silicate minerals. The silicates also fill fractures in the sulphide grains.
| Rock Type | Rank | Composition | Texture | Relationship | Gabbro | 1 | Gabbro | Host |
|---|---|---|---|---|
| Intermediate lava flow-unsubdivided | 2 | Rhyodacite | Near | |
| Intermediate lava flow-unsubdivided | 3 | Dacitic To Rhyodacitic | Near |
Dec 07, 2005 (B Nelson) - The metavolcanics intruded by the metagabbro body are described by Faust (1973) as massive, porphyritic flows of rhyodacitic composition. Although gabbro and quartz gabbro are by far the most prominent rock types encountered, the occurrence of metapyroxenite and anorthositic gabbro suggested that more ultramafic differentiates may occur within the intrusion.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Chalcopyrite | Economic | Ore | ||||
| 2 | Pentlandite | Economic | Ore | ||||
| 3 | Pyrite | Economic | Ore | ||||
| 4 | Pyrrhotite | Economic | Ore | ||||
| Quartz | Alteration | Silicification | 1 | Unknown | Disseminated |
Dec 07, 2005 (B Nelson) - Examination of polished sections from this deposit by Faust led to the following observations: 1). po, cp and pent are present in that order of abundance. 2). po occurs as large irregular blebs, 2 to 3 mm across, commonly rimmed by cp and pent, as fine inclusions in the mafic silicates and subround blebs interstitial to the silicate minerals. 3). cp also occurs in discrete, irregular masses, in rounded to irregular blebs peripheral to and within the po and as interstitial droplets between silicate minerals. 4). pent occurs as grains peripheral to the po masses and forms flame-like exsolution lamallae along the basal po cleavage direction. Mineralized sections in drill core yielded values from trace to 0.32% Ni and from 0.01 to 0.40% Cu.
| Zone | Year | Category | Tonnes | Reference | Comments | Commodities |
|---|---|---|---|---|---|---|
| JACOBUS PROSPECT | 1974 | Unclassified | 907441 | OFR 5630 | 1974 ESTIMATE ACTUALLY LUMPS CU/NI TOGETHER, WITH A GRADE OF 0.94% | Copper .94 Percent |
| JACOBUS PROSPECT | 1969 | Unclassified | 850760 | OFR 5630 | Nickel .41 Percent |
Map - Tashota-Geraldton sheet, geological compilation series, Thunder Bay and Cochrane districts
Publication Number: M2102 Date: 1997
Author: Pye E.G., Harris F.R., Fenwick K.G., Baillie J.
Publisher Name: Ontario Dept. of Mines
Location:
Map - Elmhirst and Rickaby townships, Thunder Bay District
Publication Number: M2373 Scale: 1:31,680 Date: 1977
Author: Mackasey W.O., Wallace H.
Publisher Name: Ontario Geological Survey
Location:
Map - Thunder Bay data series, Wilkinson Lake area, District of Thunder Bay
Publication Number: P2514 Scale: 1:15,840 Date: 1982
Author: Speed A.A.
Publisher Name: Ontario Geological Survey
Location:
MonoMap - Geology of Elmhirst and Rickaby townships, District of Thunder Bay
Publication Number: R168 Page: 72-76 Date: 1978
Author: Mackasey W.O., Wallace H.
Publisher Name: Ontario Geological Survey
Location:
Mono - Gold occurrences, prospects, and deposits of the Beardmore-Geraldton area, districts of Thunder Bay and Cochrane
Publication Number: OFR5630 Date: 1986
Author: Mason J.K., White G.D.
Publisher Name: Ontario Geological Survey
Location:
File - Resident Geologist Mineral Deposit Files
Publication Number: Min Dep Date:
Author:
Publisher Name:
Location: Thunder Bay RGP
Mono - Copper, nickel, lead and zinc deposits of Ontario
Publication Number: MDC012 Date: 1969
Author: Shklanka R.
Publisher Name: Ontario Dept. of Mines
Location:
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