The Totten deposit is hosted within the Worthington Offset Dyke which extends 12 km south from the SIC. The dyke attains a thickness of 45 m in the Totten Mine area, strikes approximately 045°, and has steep variable dips.

Metasedimentary rocks and the Nipissing meta-gabbro sill underlie the Totten Mine area. The sill is 365 m thick, trends east–west and dips at approximately 65° to the southeast. The Worthington Offset cuts both the metasedimentary rocks and the gabbro sill. Late quartz diabase and olivine diabase dykes crosscut all lithologies.

The contact between meta-gabbro and Worthington Offset Dyke is characterized by a meta-gabbro breccia with fragments up to 10 m diameter. Locally the meta-gabbro is invaded by an inclusion quartz diorite stockwork and mineralized stringers. These breccia and stockwork features are not developed in metasedimentary rocks.

Two quartz diabase dykes occur in the immediate vicinity of the Totten Mine and bound the majority of the high-grade mineralization hosted in the Totten Main orebody. The quartz diabase dykes are steeply dipping and vary in thickness from <3–10 m. Quartz diabase dykes are generally fractured especially along the contacts resulting in local poor ground conditions. Several olivine diabase dykes of variable width occur to the north of the Totten Main orebody.

STRUCTURE
The Worthington Offset has been displaced by two major faults. The Creighton fault strikes east-west, is vertical to steeply dipping to the north, and dextrally displaces the Worthington Offset Dyke by approximately 1 km. The Murray fault also strikes east–west, is vertically dipping and dextrally displaces the Worthington Offset by approximately 1 km.

Between the Creighton and Murray faults the local rock mass has been subjected to northwest-southeast fracturing and weak faulting. Minor displacement occurred locally on some of the larger fractures.

MINERALIZATION
Copper–nickel–PGE–gold sulphides are hosted within an inclusion quartz diorite phase of the Worthington Offset. This sulphide zone consists of variable thicknesses of massive and semimassive copper–nickel-bearing sulphides surrounded by a disseminated and blebby sulphide halo.

The massive sulphide varies in true thickness from 2–15 m and is dominantly pyrrhotite and pentlandite. The massive sulphide thins and splays into 2.5 cm to 1 m thick copper-rich stringer zones within the disseminated sulphide halo. Semi-massive sulphides are also typically pyrrhotite and pentlandite rich, but are spatially associated with chalcopyrite-rich patches. In areas where large meta-gabbro inclusions are present, metal grades tended to be higher than in portions of the dyke containing only amphibolite inclusions.

Thick, localized accumulations of ore are situated to the north and south of the quartz diabase dykes. Nickel and copper mineralization become progressively higher grade with depth and towards the core of the mineralization.

PGE–gold minerals are spatially associated with more copper-rich sulphides. Platinum and palladium grades increase with depth but the gold grade does not. The highest PGE–gold grades are concentrated at depth around a portion of the southernmost quartz diabase dyke.

Mineral zone boundaries are locally characterized by arsenic-bearing minerals such as niccolite and gersdorffite. Niccolite stringers are also encountered in the quartz diabase dyke and sometimes in quartz diorite and inclusion quartz diorite proximal to the Worthington Offset.

Totten Mine is located in Worthington, Ontario, 15 km west of Sudbury. The Totten Mine deposits consists of the actively mined Totten Main (215), and other mineralized zones including the 230, 260, 242, 235, 238, 238 West, Howland, and McIntyre zones.

The 1,260 m (4130 ft) deep #2 Shaft is the primary entry and exit point into the mine for personnel, materials and ore/waste.

The secondary means of egress is a ladder system from surface down to the 4530 Level. A ramp has been connected to shaft access levels on the 3850 and 3150 Levels and it serves as second egress for the workings between the 3150 and 3800 Levels. Apart from the shaft, ramp access now exists from the 4650 to 2330 Levels. When ramp development is completed, mine will have ramp access from the 1850 to 4630 Levels.

Slot–slash and Mechanized cut-and-fill mining methods are employed for ore extraction. Most of the main ore body at the Totten Mine is mined using transverse primary–secondary stoping. Longitudinal stoping is used in narrow portions of orebodies and in stopes adjacent to trap dykes.

Alluvial sands are used for backfilling.

Loading equipment includes 7.2 t, 9 t and 5.4 t capacity LHDs. Smaller 2.3–3.2 t LHDs are used as utility equipment.

The dewatering system design at Totten consists of two main sump stations and level settling sumps. The main sump stations are located on the 2,000 and 4,000 Levels; settling sumps are located on all main production levels. The main pumping station on the 2,000 Level discharges to surface at a rate of 800 gallons/minute. Water is pumped via the shaft up to the 2,000 Level and then from the 2,000 Level sump station up through boreholes to the 1,850 Level and then to surface.

Ventilation System consist of one major fresh air system and one main return air system and has 685 kcfm capacity.

The process plant design was based on a combination of metallurgical testwork and familiarity gained during historical processing. The Clarabelle Mill was originally built in 1971 and subsequently underwent a number of major modifications. The hourly design throughput of the plant was based on a yearly throughput of approximately 8 M tons. The utilization calculation was that the plant would operate 350 days per year, with an availability of 92%, for a net utilization of 88.2%. In 2017, the crushing plant and rod mill circuit was put on care and maintenance and the Clarabelle Mill became a SAG-only operating plant. The yearly throughput based on SAG-only operation is approximately 6.0 Mt.

At the concentrator, the ore is crushed and ground and fed to the froth-flotation cells. The multistaged froth flotation separates the sulphide minerals into a nickel concentrate and a copper concentrate. The tailings are disposed of in tailings ponds. The nickel concentrate typically aver ........