The magmatic copper-nickel sulphide deposits at Sudbury are part of the Paleoproterozoic Sudbury Structure which comprises the Sudbury Igneous Complex (SIC); breccias, mudstones siltstones and wackes of the Whitewater Group which occupy the centre of the Sudbury Basin; and a ring of brecciated and shockmetamorphosed Archean and Paleoproterozoic footwall rocks which surrounds the SIC. All rocks defined as footwall to the Sudbury Structure are cut by occurrences of Sudbury Breccia. This breccia occurs as small veins, irregularly shaped patches and large, laterally extensive, crudely tabular bodies, which may extend for many kilometres along strike. The rocks of the SIC, dated at 1.85 Ga, are exposed within an elliptical or beanshaped ring with a NE-trending long axis of 60 km and a short axis of 27 km.

The rocks of the Sudbury Structure, and specifically rocks of the SIC and Whitewater Group, are affected by several fault sets and by ductile and brittle deformation associated with these faults. The Sudbury Structure is cut by a number of regional and local mafic dyke swarms. Archean footwall rocks on the North Range are crosscut by north-south trending dykes of the ~2.454 Ga Matachewan swarm.

Northwest-trending olivine tholeiitic dykes of the Sudbury swarm, dated at 1.238 Ga, crosscut the SIC and all rock units within and surrounding the Sudbury Structure.

North Range contact-type Ni-Cu deposits occur at the base of the SIC in association with ........

The Ontario Operations use conventional bulk stoping or narrow vein cut-and-fill mining methods, depending on the mine and geological setting. Mines are Owner-operated, and use conventional equipment.

Vale has technical guidelines and procedures in place to ensure that valid geotechnical data are collected and interpreted using appropriate methods, and that existing or planned risk mitigation measures that support mine designs are based on those data and interpretations. Geotechnical data collection and rock mass characterization are used to define geotechnical domains.

For each domain, ground support designs are specified that take into account geotechnical conditions, excavation service life and geometry, proximity to present and future openings, personnel exposure, local historical experiences, and local regulations. Geotechnical recommendations for vertical development, lateral development, and mining stopes, are provided. Legacy workings and drill holes with respect to mine plans are considered to ensure these hazards are mitigated.

All underground mines must have an effective Ground Control Management Plan, also referred to as the “Mine Design Package”, which is a single coherent document that must be developed through application of sound geotechnical engineering practices, conform to local mining regulations, and be aligned with Vale’s safety standards. Within the mine design package of each seismically active mine, there is a Seismic ........

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