Ontario Geological Survey
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MDI42E13NW00004
| Record Name(s) | Twin Falls Occurrence - 9999, Atlantic Mining Option - 9999 |
|---|---|
| Related Record Type | Partial |
| Record Status | Occurrence |
| Date Created | 1997-Jan-30 |
| Date Last Modified | 2022-Jan-05 |
| Created By | B Nelson |
| Revised By | B Nelson |
Primary Commodities: Gold
Township or Area: Irwin
Latitude: 49° 44' 58.95" Longitude: -87° 52' 50.7"
UTM Zone: 16 Easting: 436552.54 Northing: 5511174.888 UTM Datum: NAD83
Resident Geologist District: Thunder Bay North
NTS Grid: 42E13NW
Point Location Description: Trenches, stripped areas.
Location Method: Other Literature
Access Description: The property is located in northwestern Irwin Township, about 1 km northeast of Twin Falls, Sturgeon River (Namewaminikan River). Travel north from Highway 11 along secondary Highway 801 (Paint Lake Road) to the Sturgeon River crossing. From this point continue north for 1 km and turn left onto the River or 72 Road (second road west, north of the river). The road winds westerly for 10.5 km and turns south (main road) at the Hilda Holm intersection. Continue south for about 1.7 km to a second intersection and take the left fork, heading east. Travel for less than 1 km and turn north on a new road into the showing, which lies along the eastern shore of Little Max Lake (unnamed on map).
1934: Cyril Knight Prospecting Co. Ltd. staked a 6 claim group near the mouth of the Crooked Green Creek in the extreme north central portion of Irwin Township (now included in the 41 claim group). Stripping and trenching centered around a gold bearing quartz vein. The claims were later cancelled. A second gold showing was also discovered in the area by A. Milroy and R.S. Taylor, located 1.3 km northwest of the Cyril Knight Occurrence. A group of 9 claims was staked centering around a small lake in southern Pifher Township. Some surface exploration was completed in 1935 with interesting results. The claims became known as the Milroy-Taylor Group and the actual occurrence is locted on present day claim TB7467491. 1983: P. Skalesky and J. Ternowski staked a group of 41 claims centered on the Pifher-Irwin Township boundary, adjoining the Brenbar Mines property to the east and the 4 claim Reiter patents to the west. 1985: The 41 claim group was optioned to Atlantic Mining Corp. Stripping and channel sampling have been completed to date. All of the present activities are centered around what has become known as the 'Twin Falls Occurrence' in the extreme southwest portion of the claim group (claim TB746758).
Province: Superior
Geological Age: Archean
Dec 07, 2005 (B Nelson) - The geological setting in the vicinity of the property is dominated by Archean, intermediate to felsic metavolcanic rocks--a portion of the Onaman-Tashota belt. Many of the gold occurrences in this region are stock-related and located at the margins of intrusive igneous bodies. This includes both granite-granodiorite bodies and younger diabase dykes and sills. Locally the claim group is underlain by feldspar and quartz-feldspar porphyry, and medium to coarse felsic volcanic breccia (agglomerate). A regional break, known as the Paint Lake Fault, lies approximately 4 km to the south and marks the northen boundary of the main Beardmore-Geraldton belt. A secondary break (Musca Lake Fault) traverses the southern boundary of the claim group and may have contributed to the intense shearing seen at the Twin Falls Occurrence. The foliation and general trend of the rocks underlying the claim group is southeast ranging from 90 degrees to 115 degrees, with a steep southerly dip. A significant showing, known as the Twin Falls Occurrence, has been uncovered in the extreme southwestern portion of the 41 claim group. Power stripping has revealed a 60 m wide zone, adjacent to the swamp along the eastern shore of the lake, consisting of a highly sheared and sericitized quartz-eye feldspar porphyry or felsic tuff. The zone strikes E-W at 102 degrees and dips steeply to the south. The only 2 documented occurrences within the 41 claim group are located to the east and northeast from the Twin Falls showing. Both are quartz-vein related, as opposed to the zonal nature of the Twin Falls Occurrence.
| Rock Type | Rank | Composition | Texture | Relationship | Intermediate lava flow-unsubdivided | 1 | Near |
|---|---|---|---|---|
| Felsic lava flow-unsubdivided | 2 | Near | ||
| Granite | 3 | Near | ||
| Diabase | 4 | Diabase | Near | |
| Feldspar Porphyry | 5 | Feldspar | Near | |
| Quartz-Feldspar Porphyry | 6 | Quartz-Feldspar | Sheared | Host |
| Breccia-unsubdivided | 7 | Agglomerate | Near | |
| Felsic Tuff | 8 | Tuffaceous | Host | |
| Sandstone | 9 | Arkose | Tuffaceous | Near |
| Vein | 10 | Quartz | Near |
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Pyrite | Economic | Ore | ||||
| 2 | Gold | Economic | Ore | ||||
| 1 | Quartz | Economic | Gangue | ||||
| Quartz | Alteration | Silicification | 1 | ||||
| Sericite | Alteration | Sericitization | 2 | ||||
| Carbonate | Alteration | Carbonatization | 3 |
Dec 07, 2005 (B Nelson) - Pyrite mineralization is pervasive throughout the Twin Falls Occurrence. It occurs as fine subhedral to euhedral grains comprising from 1% to 3% of the rock. It also occurs as more massive, discontinuous bands up to 5 mm in width and in a few locations, as massive 'veins' as much as 3 cm wide. From the limited amount of sampling completed to date, it is in these zones of more massive pyrite mineralization that the highest gold assays occur. The main showing on the Milroy-Taylor group consists of a quartz vein, 9 inches in width. In one place, specks of visible gold were observed. Quartz veins on the Cyril Knight Prospecting Co. block are well fractured and milky white and carry a little pyrite in addition to the gold. Channel sampling disclosed no commercial gold values; the best sample is said to have yielded 0.64 oz/ton Au over a channel width of 9 inches. The showing is reached by a trail leading from the middle of the ox-bow stream just west of the mouth of Crooked Green Creek.
Dec 07, 2005 (B Nelson) - At approximately 30 m intervals along strike to the east, backhoe cross-trenching has exposed the pyritic shear zone to line 225 m. A large amount of gossan, quartz-filled shears, and silicification/carbonatization alteration were noted in the area (Twin Falls Occurrence).
Date: Jan 30, 1997
Geologist: B Nelson
Notes: The Beardmore-Geraldton Economic Geologist visited the occurrence August 7, 1985 and October 24, 1985.
Map - Dorothea, Sandra and Irwin townships, Thunder Bay District
Publication Number: M2294 Scale: 1:31,680 Date: 1974
Author: Mackasey W.O.
Publisher Name: Ontario Division of Mines
Mono - Gold occurrences, prospects, and deposits of the Beardmore-Geraldton area, districts of Thunder Bay and Cochrane
Publication Number: OFR5630 Scale: Date: 1986
Author: Mason J.K., White G.D.
Publisher Name: Ontario Geological Survey
Map - Sturgeon River gold area, District of Thunder Bay, Ontario
Publication Number: ARM45A Scale: 1:63,360 Date: 1998
Author: Bruce E.L., Laird H.C.
Publisher Name: Ontario Dept. of Mines
MonoMap - Geology of Dorothea, Sandra, and Irwin townships, District of Thunder Bay
Publication Number: R122 Scale: Date: 1975
Author: Mackasey W.O.
Publisher Name: Ontario Division of Mines
Map - Tashota-Geraldton sheet, geological compilation series, Thunder Bay and Cochrane districts
Publication Number: M2102 Scale: Date: 1997
Author: Pye E.G., Harris F.R., Fenwick K.G., Baillie J.
Publisher Name: Ontario Dept. of Mines
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