Ontario Geological Survey
Permanent Link to this Record:
MDI000000001840
| Record Name(s) | Prairie Lake Niobium - 2014, Good Hope - 2017 |
|---|---|
| Related Record Type | |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 2015-Apr-30 |
| Date Last Modified | 2023-May-26 |
| Created By | |
| Revised By |
Primary Commodities: Niobium, Phosphate
Secondary Commodities: Thorium, Rare Earth Elements
Township or Area: Killala Lake Area
Latitude: 49° 2' 46.69" Longitude: -86° 43' 52.69"
UTM Zone: 16 Easting: 519635 Northing: 5432638 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 42E02SE
Point Location Description: Pit
Location Method: Field Visit with GPS
Access Description: The Prairie Lake Niobium occurrences are located approximately 45 km northwest of Marathon in the Killala Lake area. Access to the site is obtained by travelling north for 29 km along the Deadhorse Road from the junction with Highway 17 to the intersection with a secondary logging road. The secondary logging road is grown-in and can be travelled by an all-terrain vehicle for a distance of 1 km northward to the area of the surface showings.
2003–06: Airborne magnetic and electromagnetic surveys, structural interpretation of remote sensing data, and soil sampling for kimberlite indicator minerals by Ripple Lake Diamonds Inc. 2011: Prospecting, bedrock sampling, radiometric surveys, soil sampling, trenching, channel sampling and assays by Canadian International Minerals Inc. 2012–14: Prospecting, sampling, trenching and outcrop stripping, and assays by R. Wahl. 2015; MDN Inc. carried out prospecting, a geological survey, trenching, and sampling. 2016: R. Wahl contracted a heliborne magnetic and radiometric survey. 2017: Plato Gold Corp. optioned the property and conducted prospecting, mapping, and sampling.
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| 2.50419 | 20000007251 | 20000007251 |
| 2.34025 | 20000001927 | 20000001927 |
| 2.31534 | 20000001165 | 20000001165 |
| 2.58157 | 20000015102 | 20000015102 |
| 2.56230 | 20000014692 | 20000014692 |
| 2.56640 | 20000014693 | 20000014693 |
Province: Superior
Subprovince: Quetico
Geological Age: Archean
May 26, 2015 (Mark Puumala) - The following is excerpted from OFR 6103: Only regional-scale geological mapping information (i.e., at 1:250 000 scale) is available for the claim on which the Prairie Lake Niobium occurrences are located. Map 2232 (Carter, McIlwaine and Wisbey 1973) indicates that the area is underlain by granitic rocks, while the most current digital geological map coverage (Ontario Geological Survey 2011) indicates that the rocks of this area are of metasedimentary origin. Sage (1987) mapped rocks immediately to the north of the Prairie Lake carbonatite complex as highly carbonatized, fine-grained (possibly metavolcanic) country rocks.
| Rock Type | Rank | Composition | Texture | Relationship | Carbonatite-Unsubdivided | 1 | Is |
|---|
May 26, 2015 (Mark Puumala) - The following is excerpted from OFR 6103: During 2014, R. Wahl discovered niobium- and phosphate-bearing carbonatite rocks on claim 4256251. The mineralized rocks were found following the manual excavation of pits at locations where anomalous readings were obtained during prospecting with a hand-held scintillometer. Grab sample assays of up to 1.63% Nb205 and 20.6% P2O5 have been reported for grab samples collected from the discovery site (Rudy Wahl Prospecting, Prairie Lake niobium – phosphate discovery Web page, January 9, 2015). These rocks also contain anomalous levels of uranium and thorium, accounting for the scintillometer response. A petrographic analysis of samples collected from the new Prairie Lake Niobium occurrence was performed by Dr. R. Mitchell (Lakehead University) during 2014. This petrographic work identified the following minerals in the carbonatite intrusion: calcite, ferroan dolomite, calco-siderite, apatite, pyrochlore, barite, ancylite, synchisite, iron oxides and hydroxides, quartz, potassium feldspar, pyrite and fluorite. Pyrochlore is the niobium-bearing mineral in these rocks, while phosphate occurs in apatite. Unlike other niobium occurrences in the Prairie Lake area, the pyrochlore here is thorium-free and low in uranium. This is a desirable characteristic because low levels of radionuclides are less problematic when processing niobium-bearing ore. Additionally, Mitchell reported that the pyrochlores at this location are large (up to 1 mm), suggesting that their separation from apatite and carbonates should be straightforward (Rudy Wahl Prospecting, Prairie Lake niobium – phosphate discovery Web page, January 9, 2015). The niobium occurrences occur within a prominent magnetic “low” that occurs on the northwestern flank of the Prairie Lake carbonatite complex (see Figure 11). Although the negative magnetic anomaly is most pronounced to the northwest, it wraps around the entire northern margin of the complex, merging with a north-trending anomaly. The north-trending anomaly has a close spatial association with a phosphate, niobium and rare earth element (REE) occurrence in float (Site #6) that was discovered by R. Wahl on claim 4246264, located north of Ruffle Lake.
| Rank | Classification |
|---|---|
| 1 | Carbonatite |
Date: Oct 09, 2014
Geologist: Mark Puumala
Notes: Exploration pits at R. Wahl's Prairie Lake niobium discovery Sites #1 (UTM Zone 16, 519635E, 5432638) and #2 (UTM Zone 16, 519599E, 5432417) were visited by D. Campbell and M. Puumala of the Thunder Bay Resident Geologist Program office on October 9, 2014. The dominant lithology in all pits is a medium-grained carbonatite that has a rusty reddish brown or yellow-brown rind up to 3 cm thick on weathered surfaces. Sage (1987) described a similar rock type, classified as ferruginous carbonatite, that occurs along the western side of the Prairie Lake carbonatite complex. The fresh surface of the rocks from the pits at Site #1 and Site #2 reveal fenitized, brecciated and mottled carbonatite with a wide variety of colours including various shades of pink, red and purple. The rock is composed mostly of carbonate minerals with coarse green and/or black amphiboles, +/- mica. Brecciated material includes angular to subrounded fragments cross-cut by buff-white carbonate stringers. At Niobium Site #1 in Pit #2 (a 1 by 1.5 m excavation), the main carbonatite mass is cross-cut by a white to light pink, coarse-grained carbonatite phase that contains fine-grained disseminated sulphides. This pit also exposes mica-rich rock (possibly altered country rock) that is cross-cut by a narrow carbonate seam. The rocks display a well-developed layering fabric that strikes 240 degrees, with a dip of 55 degrees to the northwest. The pit at Niobium Site #2 has dimensions of about 2 by 2 m, and is located approximately 200 m south-southwest of Niobium Site #1 The pink, niobium-bearing carbonatite here is similar to that observed at Niobium Site #1, with the exception that it contains disseminated pyrite. Country rocks near Niobium Site #2 strike 190 degrees with a dip of 65 degrees to the west. The structural measurements at both sites indicate that rock fabrics in this area dip moderately away from the Prairie Lake complex. Niobium assay results for samples of the medium-grained pink carbonatite that were collected from pits at both occurrence sites ranged from 0.047 to 1.432% Nb2O5, while phosphate results ranged from 0.15 to 10.49% P2O5. The most significant niobium assay result was obtained from a sample collected from Pit#1 at Niobium Site #1 (MPRWN1402). The best phosphate result was obtained from Niobium Site #1, Pit#2 (MPRWN1405). Interestingly, the sample with the lowest niobium concentration (14DCRW008) contained the highest concentrations of thorium and rare earth elements. The apparent inverse correlation between thorium and niobium levels is consistent with petrographic data, indicating that the niobium-bearing pyrochlore is thorium-free (i.e., thorium is present in another mineral phase). Samples of the coarse-grained white carbonatite and the altered country rock collected from Niobium Site #1, Pit #2 both returned assays with very low niobium concentrations.
Mono - Report of Activities 2014, Resident Geologist Program, Thunder Bay South Regional Resident Geologist Report: Thunder Bay South District
Publication Number: OFR6303 Date: 2015
Author: Puumala M.A., Campbell D.A., Tims A., Debicki R.L., Pettigrew T.K., Brunelle M.R.
Publisher Name: Ontario Geological Survey
Location:
Map - Geological series, Sturgeon Narrows and Squaw Lake alkalic rock complexes, District of Thunder Bay
Publication Number: P2223 Scale: 1:15,840 Date: 1980
Author: Trowell N.F., Sage R.P., Wright W., Chamois P., Higgins C.
Publisher Name: Ontario Geological Survey
Location:
Mono - Geology of carbonatite-alkalic rock complexes in Ontario: Prairie Lake carbonatite complex, District of Thunder Bay
Publication Number: S046 Date: 1987
Author: Sage R.P.
Publisher Name: Ontario Geological Survey
Location:
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