Deposit/occurrence name: Jeanette, Sapphire
Deposit Status: Occurrence
Township Area: Timmermans
Workings: Pits, drill holes
Nearest City/Town Elliot Lake
Primary Commodity: Uranium
Secondary Commodity: Thorium
Grade of Deposit: 0.02% U308 and 0.02% ThO2
Prospect location: Big Moon Lake area.
Last Exploration: 1967 - Denison Mines, Ltd.
Deposit Type Pyritic/Conglomerate/granite
Access: Boat in or Bush walk
History and location:
It was in 1953, when a total of 14 pits were sunk over a distance of 1 mile by Moneta Mining Company before the property was drop. At the beginning of 1954, Geological and airborne scintillometer surveys and a diamond drilling program of five surface hole, totalling 2,406 feet was completed by Jeanette Minerals, Ltd. Jeanette Minerals was rather a company that was renamed from the Consolidated Mattarrow Mines, Limited. Most of this had taken place in conjunction to merges that were happening in regards to uranium exploration. Most of this had been caused as the interest for uranium would end up increasing its market values to warrant exploration work. With increasing markets this had caused many of the smaller base-metal producers to change their own names as uranium was becoming a target for exploratory work. The name was mainly changed in conjunction with Sapphire Petroleum's Limited, 25% interest that was held on a block of 18 unsurvey claims. These claims were generally located between Moon Lake and Little Moon Lake in central Township 161 (Now Timmermans). At this time, it was reported that the group was best reached via Matinenda Lake and either Moon or Little Moon Lakes.
One last exploration of the general area was being done by Denison Mines, Limited, in 1967. This resulted in completing a combined Airborne Mag and EM Survey in part of its wide spread uranium exploration program in the Elliot Lake Area. No other work was done by this company at the time.
Geology of Jeanette Uranium-Thorium Prospect
This property is rather crossed diagonally from northwest to the southeast by the Moon Lake Fault and a diabase dike. Its also to the northeast of these structures that there is an exposure of upper members of the Lower Mississagi arkose and quatzite with scattered, thin, oligomictic pebble band. In addition to this, quartz veins and much shattering are also well developed close to the fault zone location. Some of the exposures of conglomerate to the north-shore of the headland on the east shore of Moon Lake, were trenched, and five shallow drillholes were drilled. No intersections which contain more than 0.02% U3O8 was reported, and no further development or exploration work was undertaken. This location generally contains radioactive pyritic oligomictic pebble conglomerate of the Matinenda Formation. Some of the average assays were from 0.029% U3O8, and 0.02% ThO2 over 28 feet at the time. The area is also generally hosted by a granitic pegmatite that contains pebbly pyritic conglomerate.
The Lower Mississagi Formation is exposed as the following, with the upper members that are generally exposed between to faults as the northwest end of Rosssmere Lake in McGiverin Township. It also commonly a belt, that partcially interrupted by faults and diabase intrusions, extending from the southwest corner of McGiverin Township by Intersect, McFadden, Hastie, Surprise Lakes and the North Shore of Lauzon Lake to the Pronto Uranium Mine. Its from the east end of Long Lake that's northeast of the Pronto Mine along Spragge Creek swinging east along Waugush Lake to the vicinity of Highway # 108 where the formation is cut by overlap against a basement topographic high. The entire Lower Mississagi Formation is also only exposed in vicinity of Surprise Lake and the east end of Lauzon Lake, and to the east of Waugush Lake. In addition to surface data there is considerable information from diamond drilling.
The Lower Mississagi Formation rather rests with unconformity on the surface of the Algoma Granite and relicts of the post-Algoman solids that are normally preserved. The actual base of the Lower Mississagi Formation is marked by the onset of sorting, and bedding. This usually consists of beds of quartzite pebbles that are largely present with in the contact that may be difficult to identify particularly in drill core. The lowermost beds which generally consist of poorly sorted, angular to subangular quartzite and microline grains that are up to 1/4 inch across, set in groundmass of continued fragments and sericite, while the latter probably had derived from the weathered granite. In some cases, pyrite is largely present within the quartzite that constitutes as a sulphide mineral but is not present in all geological environmental conditions. These foremost beds are considered to crudely grade into finer grained more sericitic material that's more significant towards the top. Interbedded wit the arkosic quartzite are beds up to 4 inches thick consisting largely of sericitic feldspar debris and quartz. On weathering these beds take on a much yellow green colour that's more pronounced than that of the quartzite. On certain outcrops these rather green bands are clearly defined by the bedding. The upper most surfaces of the quartzite and green band may also show ripple marks.
Quartzite beds are generally scattered throughout the arkosic beds or concentrated into bands generally 1-3 inches thick. These pebbles are subangular to well rounded, well sorted, and are almost entirely of vein quartz, although pebbles of chert, jasper, and occasionally, deformed clasts are similar to the sericitic green beds. Pyrite is commonly conspicuous component of the matrix of the pebble bands. The pyrite may be euhedral or anhedral, and is largely restricted to the matrix it self. Some of the main accessory minerals consists of monazite, magnetite, apatite, and zircon. These pyritiferous oligomictic pebble bands are slightly radioactive that are generally less than 3 times background. They are also similar in type to the uranium-thorium ore of the Blind River Group.
The Lower Mississagi Formation is there for determined as dominantly coarse-grained arkose-quartzite sequence derived from weathered granite and deposited in much shallow water by southeasterly flowing currents. A zone of greater thickness may also lie in the most southwest part of Long Township. Scattered pebble bands and radioactivity are some of the main characteristics of the lower part of the formation. Radioactive conglomerate that's to the east end of Lauzon Lake had additionally sparked the Blind River Staking Rush.