The Labrador Trough contains four main types of iron deposits:
- Soft iron ores formed by supergene leaching and enrichment of the weakly metamorphosed cherty iron formation; they are composed mainly of friable fine-grained secondary iron oxides (hematite, goethite, limonite).
- Taconites, fine-grained weakly metamorphosed iron formations with above average magnetite content, which are also commonly called magnetite iron formation.
- More intensely metamorphosed, coarser-grained iron formations, termed meta-taconites; that contain specular hematite and subordinate amounts of magnetite as the dominant iron minerals.
- Occurrences of hard high-grade hematite ore occur southeast of Schefferville at Sawyer Lake and Astray Lake.

The Sokoman iron formation was formed as chemical sediment under varied conditions of oxidationreduction potential (Eh) and hydrogen ion concentrations (pH) in varied depths of seawater. The resulting irregularly bedded, jasper-bearing, granular, oolitic and locally conglomeratic sediments are typical of the predominant oxide facies of the Superior-type iron formations, and the Labrador Trough is the largest example of this type.

The facies changes consist commonly of carbonate, silicate and oxide facies. Typical sulphide facies are poorly developed. The mineralogy of the rocks is related to the change in facies during deposition, which reflects changes from shallow- to deep-water environments of sedimentation. In general, the oxide facies are irregularly bedded, and locally conglomeratic, having formed in oxidizing shallow-water conditions. Most carbonate facies show deep-water features, except for the presence of minor amounts of granules. The silicate facies are present in between the oxide and carbonate facies, with some textural features indicating deep-water formation.

The carbonate, silicate and oxide facies contain typical primary minerals ranging from siderite, minnesotaite, and magnetite-hematite respectively. The most common mineral in the Sokoman formation is chert, which is closely associated with all facies. Carbonate and silicate lithofacies are present in varying amounts in the oxide members.

The sediments of the Labrador Trough were initially deposited in a stable basin that was subsequently modified by penecontemporaneous tectonic and volcanic activity. Deposition of the iron formation indicates intraformational erosion, redistribution of sediments, and local contamination by volcanic and related clastic material derived from the volcanic centers in the Dyke-Astray area.

The Joyce Lake DSO is an enrichment zone along the nose of the main fold of the Joyce Lake syncline. This enrichment extends laterally within the iron formation forming a vase (bowl) shape with significant thickness in the hinge of the syncline.

Mining of the Joyce Lake deposit will generally follow the standard practice of a conventional open pit operation, with drill and blast, load and haul cycle using a drill/shovel/truck mining fleet. The overburden and waste rock material will be delivered to the overburden and waste disposal areas near the pit. The run of-mine ore will be delivered to the ore stockpile or low grade stockpile.

The mining operations division will consist of the pit operations, maintenance, engineering and geology departments.

Mining phases, including initial overburden and waste pre-stripping requirements and a mining schedule was developed. The starter pit was designed to avoid excavation close to Joyce Lake during the pre-production and construction phases. The open pit production schedule has been developed on a 4-month basis for the life of-mine (LOM) and was developed based on a fixed production target of 2.5 M dry tonnes per year of iron ore lump and fines products at an average grade of 60 to 62% Fe.

Annual mining equipment fleet requirements were developed based on equipment performance parameters and average hauling distances based on pit design and configuration and location on the site plan for the crusher and waste piles. The primary equipment fleet includes 96- tonne diesel haul trucks, 10 m3 diesel-hydraulic shovels, 10 m3 front-end loader and 8.5” down the-hole (DTH) blast hole drills.

The Joyce Lake DSO flowsheet consists of a two stage dry crushing and screening process to produce “lump” and “fines” products. A two stage crushing circuit is required to produce material at the target size of 100% passing 31.5 mm.

Process design is based on mining haul trucks delivering material from the open pit mine to the ROM ore stockpile area ahead of the process plant. Sufficient stockpiling space is provided to allow for segregating ore to allow for blending feed materials ahead of the process plant to minimize product grade variability. A dedicated front end loader of 16 t capacity is used for maintaining the ROM stockpile and for feeding the process plant.

The front-end loader transfers material from the ROM stockpile to a feed hopper fitted with a static grizzly screen to scalp off any oversized material (+600 mm). No rock breaker is provided as the +600 mm material will be rejected to a stockpile to be processed later. Once a sufficient quantity of material has accumulated, a contractor will be used to break the oversize rocks for processing. The material passing the static grizzly is directed onto a vibrating grizzly feeder that serves to separate material at 130 mm prior to the primary crushing stage. The oversize material (+130 mm) is fed to a jaw crusher where it will be crushed to a top size of 225 mm. The undersize material from the static grizzly joins the jaw crusher product and the materials are combined on a common collecting conveyor. This blended material is conveyed to a triple deck horizontal screen that separates the material into three products:
- The oversize +31.5 mm material is conveyed from the top screen deck to a cone crusher for further size reduction to a targeted top size of 32 mm;
- Lump product (-31.5/+6.3 mm);
- Fines product (-6.3 mm). The material discharged from the cone c usher is returned to the triple deck screen. The cone crusher is therefore in closed loop with this screen thus ensuring that no material coarser than 31.5 mm is sent with the final lump product. While a double deck screen would normally suffice to separate the material into oversize, lump and fines products, a third deck was added to relieve the load on the 6 mm screen. This was done in order to alleviate excessive bed depth issues and inefficient screening that might be encountered in separating the fines and lump products. Each of the two final lump and fines products is discharged via a chute onto its respective collecting conveyor and subsequently to its respective stockpile using an appropriately designed conveyor stacking system. Each product stockpile has a design capacity to hold 16 hours of material to allow for scheduled plant maintenance shut-downs. A dedicated front-end loader of 16 t capacity is used to load product from the product stockpiles into product haul trucks that deliver product to the load-out and rail loop area.

Although annual product production and sales have been determined based on the annual mine plan of 2.5 Mtpa ore tonnes, the process plant design has been based on an annual maximum production of 3.0 Mtpa of product.