The Bracemac-McLeod deposits comprise a cluster of polymetallic VMS lenses, which are generally thinner and of a more complex morphology than the historic deposits in the Matagami mining camp. All shallower deposits are now mined-out and only the McLeod Deep lens remains, which lies between depths of 980m and 1,440m. The underground diamond drilling campaign was completed in July 2019 and since September 2019 the geological model for this deposit has only been updated based on underground geological mapping. The Deep lens is now classified as a Measured Resource.

Bracemac Property
The deepmost unit is the Watson Lake Rhyolite, a gray to gray-green fine-grained amygdular rhyolite with 3–5% 1–3 mm quartz phenocrysts. The amygdules (3–7%) are quartz-filled and range between 0.3 and 3 cm. The texture of the rhyolite varies locally and includes breccia and flow banding, as well as massive flows. Near the VMS deposits, the rhyolite can be strongly chloritized to a soft black chlorite alteration pipe texture, with silica addition along fractures and in breccia, creating a “snake-skin” appearance.

In the Bracemac and McLeod areas, the KT is overlain by the Bracemac Rhyolite, a fine-grained quartziferous amygdular rhyolite which ranges between 25 and 60 m thick. The unit is mostly massive, but there are some flow textures and minor breccias. Typical alteration sequences are hydrothermal chlorite and locally pervasive sericitization.

The top of the Bracemac Rhyolite is marked by the Bracemac Tuffite (BT), another finely laminated sequence of tuff and sedimented chert and sulphide precipitates. The BT is typically 10 to 20 cm thick.

McLeod Property
The deepmost unit is the Watson Lake Dacite (WLD), which is only observed in the deeper holes MC-04-01 and MC-04-03. This unit is massive, homogenous, and finegrained, with spherules and some 3–10 mm quartz-calcite–filled amygdules. At the upper boundary, this unit grades smoothly into the rhyolite as a phase transition.

The Watson Lake Rhyolite (WLR) is estimated to be at least ~200 m thick in this area. It is a fine-grained, quartziferous (up to 15%), and massive unit with some flow and dome-breccia textures. Hydrothermal chlorite alteration is strong near the sulphide deposits, showing soft black chlorite pipe textures with sulphide and quartzchlorite-pyrite-chalcopyrite-sphalerite veins. The McLeod stringer zone lies primarily in the WLR, but is sub-parallel to the stratigraphy, and cuts into the Bracemac Rhyolite towards the northeast.

Matagami mine includes three active mining sites, namely the Mine Lac Matagami (MLM) site where the concentrator, the tailings site and the Bracemac-McLeod mine are located, two closed sites for restoration, namely Orchan and Persévérance, as well as five restored sites subject to regular monitoring, namely Bell-Allard, Isle-Dieu, Garon-Lake, Norita and Radiore.

A first section of underground ramp 2.4 km long provides access to the Bracemac deposit. This then extends for 1.2 km to reach the McLeod deposit. By the end of the McLeod Deep lens operation, the ramp will have reached a length of approximately 10 km. The ramp portal is located in the mining pit of the Bell-Allard South site. A network of ramps allows the exploitation of the Bracemac and McLeod deposits which extend respectively from 70 m to 600 m and from 360 m to 1490 m in depth from the ground surface.

Ore mined from the Bracemac-McLeod mine is processed at the MLM site's concentrator to produce zinc and copper concentrates. Tailings are sent to the tailings site. Waste rock is used underground as a rock fill, whether cemented or not. The main infrastructures as well as the access ramp portal are located on the former Bell-Allard Sud site; an old open pit operated between 1968 and 1970.

The current extraction method at Bracemac-McLeod is sublevel open stoping.

Operations are maintained 365 days a year.

The Bracemac and McLeod deposits consist of several lenses rich in zinc and copper with low silver and gold grades as well.

The extracted ore is transported by truck on a towpath to the concentrator of the Mine Lac Matagami (MLM) site.

The ore sent to the MLM site is crushed and then sent to the concentrator for processing to produce zinc and copper concentrates. The process consists of a first flotation to produce the copper concentrate. The discharges from the copper circuit are redirected to the zinc flotation circuit to produce the zinc concentrate. The concentrator tailings are deposited in the Matagami Mine tailings site.