Mine or Prospect Status: Abandoned Mine Site
Type of workings: Underground and Surface workings
Township Location: Blezard Township
Closest City or Town: Sudbury, Ontario
Province and Country Ontario, Canada
Latitude: 46° 32' 42.15"
Longitude: -81° 0' 21.54"
District location: Sudbury District
Subprovince: Sudbury Structure
Belt: Sudbury Igneous Complex
Tectonic Assemblage: Sublayer Contact
Formation type: Mafic Intrusive, Ultramafic
Chemical Compositions: Quartz- Diorite, Granite, gabbro, Argillite
Common names: Little Stobie Mine
Deposit Status: Producing Mine
Primary Commodities: Copper-Nickel
Secondary Commodities: Gold, Cobalt, Platinum, Platinum Group Elements, Silver
Geological Events: Meteorite Impact Zone
Start Date: 1893
Close Date: 1894
Re-Open Date: 1967
History and Exploration of the mine
The Little Stobie Mine is rather known as a Cu-Ni deposit that’s located near a fault zone of the historical Frood-Stobie Mine Site. In 1893, the Sudbury area of Upper Canada was being widely prospected as many mine projects came to being establish. Prospecting was also carried out before that time as the projects were first place under minor development and prospecting phases in 1885. During the time period, the Little Stobie Mine was first being uncovered by a famous prospector of the area known as James Stobie. James Stobie was one of Sudbury’s first ever prospectors to come across a massive deposit of Cu- Base Metals within the PGE that became known as the Stobie Mine. Now not to get mix up between the two, the Frood-Stobie was rather a whole different operation from the Little Stobie Mine Project. Within 1893, the Little Stobie Mine was be extensively prospected within the region and was situated not to far from the Frood-Stobie Mine. It was at a point of half a mile west when Little Stobie was being further prospect by James Stobie in 1891. Much of the development at the time resulted in sinking three test pits in order to prospect the area further. Most of the work that was done had mainly been place under further follow up when three test pits were sunk at various depths of 15, 18, and 20 feet. These pits can also be seen today on what became known as the Little Stobie Mine Project that was apart of the Elise Mountain Formation, the Murray Granite, and another sublayer granite. A total of 1,584 tonnes of ore was additionally mined during the prospecting stage of the Little Stobie Mine.
A new shaft at the time was also constructed and would be designed as a concrete head-frame operation that was once 185 feet in height. Most of the operational side of the shaft was additionally operated by four rope friction hoist that operates a double-deck cage and a 12-ton bottom dump skip. Power that was obtained had also been taken from a 900 H.P Motor, in which had a hoisting speed of 1,500 feet per minute. Another shaft known as the No. 2 Shaft was mainly being used for development, and had bottomed at 1,994 feet below the surface in April, 1967. Prior to the completion of the underground development, it was also being turned into a fresh air raise. The Mine ventilation system was also designed extensively in order to supply 625,000 cubic feet of fresh air per minute. Mining of the ore-bodies at the time was principally done by sub-level caving, that was done by sub levels, in a series of vertical slices, and had removed the broken ore in assistance with controlled caving in the hanging wall rock. Pillars of ore at the time were also being left in order to support the hanging-wall rock within the Little Stobie Mine Project.
After many years of knowing that an ore-body did exist in this area, the project would not be place under further development till 1966. Much of the projects at the time which included the Little Stobie Mine was taken up by the International Nickel Company of Canada, Limited. It was at this point in time when extensive drilling had started to disclose the Cu-base metal ore-body further. As drilling comfirmed the presence of an ore-body at a depth of 400 to 500 feet, it was suggested to sink two shafts. Shaft sinking was eventually done on two separate ore-bodies which were faulted off from each other. These two ore-bodies were apart of a subsequent deposits that was formed in parts by the Elise Mountain Formation, the Murray Granite, and another sublayer granite within a norite sublayer.
The No. 1 Shaft was eventually sunk to a depth of 777 feet below the surface, in which the 400- and 600-foot levels were establish at depths of 453 and 652 feet. Another shaft known as the No. 2 Shaft was eventually sunk on a separate ore-body that had reach a depth of 1,230 feet below the surface. Several levels had eventually become developed when the 200, 400, 600, 800, 1,000, and 1,223-foot levels were cut. Each of these ore-producing levels were being engineered at depths of 231, 427, 628, 826. 1,025, and 1,223-foot horizons. Lateral development footage that was completed on these levels alone had consisted of 497 feet of drifting and crosscutting, and 177 feet of raising. A total of 90 diamond drill holes were then place to explore this area further and to do follow ups, in which totalled 85,834 feet from the surface.
Some major equipment at the time had also became establish in which resulted in installing four transformers, two being 1,500 KVA and the other two being 600 KVA. Other major equipment would also be place when the company added two Aerofoil Fans, which were 24 inches in diameter. Even more equipment would be place on this site when one mine transit and 1 transformer of 2,000 KVA 44,000/2,300 V, were installed in a temporary substation. Most of the work which was being done had also been completed under the management of MacIsaac Mining and Tunneling Company, which L. McGreedy was the Manager of the mine.
Further shaft sinking would take place when the No. 1 Shaft was now reaching a depth of 2,650 feet below the surface. This was also followed by establishing new levels that were known as the 800, 1,000, 1,200, 1,400, 1,600, 1,800, 2,000, 2,200, and 2,400-foot levels. Each of these newly cut and station levels were also being developed on the mines 852, 1,051, 1,245, 1,450, 1,650, 1,849, 2,049, 2,248, and 2,451- foot horizons. Engineering at the time had also continued onward when the No. 2 Shaft was also sunk to a depth of 1,994 feet below the surface. Much of the development work in sinking the shaft resulted in opening up the 1,400, 1,600, and 1,800-foot levels. Each of these newly cut and station levels were also opened up on the 1,425, 1,624, and 1,825-foot horizons of the Little Stobie Mine. The total development footage between the two shaft operations had consisted of 13,024 feet of drifting and crosscutting, and 618 feet of raising. It was also to the end of that year when the total development footage was now at 13.701 feet of drifting and crosscutting, and 795 feet of raising. Diamond drilling had also taken place when 15 underground holes were drill, and had a total length of 4,446 feet. It was also at this point in time when 900 tonnes of ore was taken from the mine and hoisted from the No. 1 Shaft. Equipment at the time was also added as 2 scooptrams, 44 mine cars, 4 hoists, 2 controllers, 3 transformers, 2 fans, 1 drill, 1 saw, and 6 pumps were added.
No additional sinking of the two vertical shafts was done during the operating year of 1968. Most of the work during that time period was focus on further developing the Little Stobie Mine Project. Lateral development during 1968, was also increased when 26,257 feet of drifting and crosscutting, and 5,564 feet of raising was done. A crusher station, along with an ore-bin were also excavated below the 2,200-foot level. Other contracts towards lateral development were issued to Dravo of Canada, Limited. In order to start a service ramp, which would be extended from the surface to the 600-foot level. Most of this pre-engineering plan was aimed at developing the upper portion of the mine in order to increase production and to provide access for diesel equipment. It was also at this point in time when major construction had also occurred in further developing the much needed mine buildings. Equipment at the time was also added which included 8 batteries, 1 charger, 2 compressors, 1 crane, 5 fans of 35 H.P, two dumpers, 1 feeder, 3 heaters, 17 hoists, 4 motors, 1 machine, shotcrete, 1 loader for ore, 6 pumps, 3 reducers, 1 scooptram, 1 drill, and 1 cooling tower. Ore which was hoisted during that time period of operating the Little Stobie Mine had amounted to 35.017 tonnes of hoisted and stockpiled ore.
In 1969, Level development was further continued from the No. 1 and No. 2 vertical shaft operations at the Little Stobie Mine. A minor delay during the year had rise when a strike action had occurred from July, 10 to November, 14, 1969. It was within that time period of operating when the No. 1 Shaft head-frame and hoist was dismantled in May of that year, and construction of a permanent head-frame was commenced. Much of the development work within the No. 1 shaft was continued with the use of a temporary hoist and cage installed on the 400-foot level. A service ramp which was extended from the surface down to the 600-foot level, had reach the 500-foot level by the end of 1969. The service ramp was also In use for developing a portion of the mine for initial production and would also provide access for diesel mine equipment. Lateral development footage in 1969, had consisted of 18,037 feet of drifting, and crosscutting and 2,755 feet of raising was done. Diamond drilling that was completed at the time had also amounted to 51 underground holes, totalling 18,921 feet were done, and an additional six holes, totalling 5,694 feet were completed from the surface. Major construction that was done in 1969, included concrete tunneling below grade 7 x 8 feet, and had also been extended for a length of 198 feet. This would also include a concrete block cap and the development of a fuse and compressor house. Total development footage between both shaft operations had also totalled 57,995 feet of drifting and crosscutting, and 9,114 feet of raising.
It was during this time period when the Little Stobie Mine had rather differed from other INCO mining projects in the Sudbury area. Most of the ore that was being produce through stoping and underground development was not being hoisted to the surface. As the ore was extracted it became transported underground by 4,676, 42 inch belt conveyor on the 2,400-foot elvel of the mine to the Frood-Stobie No. 9 Shaft, where a huge level 20-ton skip brings it to the surface and had dump it directly into the Frood-Stobie Mill Storage Bin. The mine is actually located at distance of mile north of the Frood-Stobie Mine and was mainly named as an enterprise that was started on the same site by the Mond Nickel Company in 1902.
The Little Stobie Mine is known to be apart of the main mass of norite in the East-Central portion of the South Range within the Sudbury Irruptive. Much of the geology within the Little Stobie Mine is considered to be quite similar in distribution to the Murray and parts of the Creighton Mine. It was also during the exploratory work by INCO when two ore-bodies were discovered in order for the company to initiate a development plan for this project. The No. 1 Ore-Body is also known to commonly lie between the footwall rocks, which includes metavolcanic and metasedimentary units, granites, and Sudbury breccias, similar to the Richardson VMS Deposit in Eldorado, Canada. Most of the hanging wall rocks of the LIttle Stobie Mine are known to include polkilitic norite that are apart of the main Sudbury Irruptive. The main ore-body known as the No. 1 is commonly known to strike N 60 degrees E, and dips NW at 55 degrees and extends for approximately 610 m, with an average of 30 m. Diamond drilling at the time had also confirmed the extend of the mineralization from the surface to a depth of 792 m below the surface.
The other Ore-Body Known as the No. 2 Deposit, strikes S 45 degrees E for approximately 273 m into the footwall rocks and is emplaced metabasalts and a boss of footwall granite. This ore-body is known to also lie between 91 m and 366 m and reaches an average width of 52 m. Most of the ore-forming deposits within the No. 2 Ore-body are known to be a similar environment towards the other offset deposits such as the Copper Cliff Offset. Most of the principal ore that make up the sublayer ore are known to also be in association with pyrrhotite, pentlandite, and chalcopyrite, with lesser amounts of pyrite, magnetite, and ilmenite.
A total of six ore types have also been observed at the Little Stobie Mine that include the following distributions:
- gabbro-peridotite with inclusions of sulfide, that included mafic and ultramafic inclusions In abundant matrix of sulfides and minor noritic material.
-Ragged disseminated sulfides with small closely packed gabbro inclusions in a scanty matrix of sulphide and subordinate nortic material.
-Disseminated sulfides blabs of sulfide that are dispersed in an inclusion bearing matrix sublayer norite.
- Interstitial Sulfide that come in association with norite that contain sulfides interstitials to euhedral silicates.
- Inclusion Massive Sulfides with varying portions of pyrrhotite, pentlandite, and chalcopyrite containing occasional rock inclusions.
- Contorted Schist inclusion sulfide, characterized by twisted fragments of schist and inclusions of quartz in a sulfide matrix. This typical sequence from the hanging wall to the footwall would be interstitial sulfide, ragged disseminated sulfide, gabbro-pentlandite inclusion sulfide, and inclusion massive sulfide. From all production it was also reported that the No. 2 ore-body had much more higher concentrations than that of the No, 1 Ore-body that's adjacent to it. There is also significant enrichment of Rh, Pd, Ir, Os. and Ru within the No. 2 Ore-body at the Little Stobie Mine. Its also reported that there is no significant differences between the two ore-bodies in relation to Cu and Ni values, nor significant and systemic variation for all the noble metals between the two different ore types. The geological environments of the No. 1 and 2 ore-bodies are also quite different in appearance as gravitational settling liquids from a silicate magma, is present in the No. 1 Deposit. The No. 2 Deposit generally resembles other offset ore-bodies of sulfides in the Sudbury area, that represents an injection of silicate magma carrying magmatic sulfides. These are also commonly considered to be concentrated in zones at the time of the intrusion in parts with the orogeny process in forming rich sulphides deposits. It also considered that the PGE enrichment in the No. 2 Ore-body is related to differing process that gave rise to the offset deposits as opposed to the sublayer deposits in the South Range.
Mineralogy Associations with the Little Stobie Mine
Platinum (Native Element) within the Lit Stobie Mine is commonly know to also be in association with iron and magnesium rich igneous rocks of the Sudbury Basin. Its also considered to have underwent a second deposition through quartz veins that become distributed through hematite, chlorine, and pyrolusite. Platinum that is also found at the Lit Stobie Mine is known to be in association with other metals such as , iridium, rhodium. Iridium and Rhodium are also commonly known to be deposits through PGE with association of Nickel Ore and Copper Ores.
Copper that is deposited within the Little Stobie Mine is commonly known to be distributed through secondary minerals. This rather known to occur as a result of interaction between copper-bearing solutions such as chalcopyrite, Azurite, and Chalcocite. Another phase how copper is distributed within the Sudbury Basin is known to be commonly through iron bearing minerals that are formed through the orogeny process.
Silver that's known to be associated with the Lil Stobie Mine is known to come as a by-product of refining. Its also commonly considered to be associated with the refining of Pb, Zn, and Cu ore that comes as a by-product. Silver that is distributed within the Lil Stobie Mine and the Sudbury Basin is also known to be formed through altercations of other silver minerals such as quartz, gold, copper and sulphides.
Pyrrhotite - (Sulphide) Is rather known to be distributed in three phases as its commonly formed through silica poor igneous rock and under metamorphic conditions. Pyrrhotite also occurs as a product that is deposited through magmatic separations, the settling of heavy minerals to the bottom of a crystallizing magma. The third of these phases is known to produce pyrrhotite in association with pentlandite that becomes the chief ore of nickel, cobalt and silver.
Pentlandite - (Sulphide) is commonly as sulphide mineral that known to also be formed through deposition and possibly the enrichment of ore from an ancient meteorite. Its also commonly known to be in association with Pyrrhotite, Chaclopyrite, and pyrite, and arsenides that constitute the ore. Pentlandite is normally known to also be formed through silica poor, intrusive igneous rocks that are widely present in the Sudbury Basin. This is also known to be one of the most important ores in forming nickel, silver, and cobalt bearing metals.
Millerite (Sulphide) is known to also be deposited within the LIl Stobie Mine as an altercation process of nickel bearing minerals such as arsenickel, Nickel, Iron-Nickel, and Pentlandite. Its typically also known as an important ore of nickel, which is widely used in metal alloys. Millerite might have also came in deposition through an ancient meteorite that had once hit the Sudbury, Basin and caused a metamorphic altercation in forming large sulphide deposits at depth. During this phase it had rather replace the silver values within the Sudbury Basin as a process of altercation.
Chalcopyrite - (Sulphide) is commonly known to be associated with the Lil Stobie Mine Site that is mainly formed under extreme conditions Chalcopyrite is also commonly considered to have undergone depositions through medium to high temperature that had been distributed within the Sudbury Basin. The other way it has also been deposited was through grain size that had become associated with igneous rocks of the Sudbury Basin. Chalcopyrite is also one of the most important sources of Copper Ore that is known to deposit low to high-grade ore in the Sudbury Basin. Chalcopyrite is also commonly known to constitute the deposition of Rhodium and Irhodium that's associated with nickel, and PGE. Its also known to be deposited through replacements of pyrite and iron that makes up the orogeny process in distributing chalcopyrite within the Sudbury Basin.