The West Ansil deposit was the first Cu discovery in 25 years in the Noranda Central Camp. It has a combined indicated and inferred resource of ~1.2 Mt. Grades for the indicated resource are 3.4% Cu, 0.4% Zn, 1.4 g/t Au and 9.2 g/t Ag. The bulk of the resource is located in three massive sulphide lenses (Upper, Middle and Lower) that are entirely within the Rusty Ridge Formation above the Lewis exhalite. The mineralization in all three ore lenses consists of massive pyrrhotite + chalcopyrite + magnetite. Semi-massive sphalerite is restricted to the upper and lower parts of the Middle lens. Massive magnetite occurs at the center of the Upper and Middle lenses, where it replaces massive pyrrhotite. A striking feature of West Ansil is the presence of abundant colloform and nodular pyrite (+marcasite) in the massive sulphides. Late-stage replacement of massive pyrrhotite by colloform pyrite and marcasite, occurs mostly along the upper and lower contacts of the lenses.

The West Ansil deposit was the first Cu discovery in 25 years in the Noranda Central Camp. It has a combined indicated and inferred resource of ~1.2 Mt. Grades for the indicated resource are 3.4% Cu, 0.4% Zn, 1.4 g/t Au and 9.2 g/t Ag. The bulk of the resource is located in three massive sulphide lenses (Upper, Middle and Lower) that are entirely within the Rusty Ridge Formation above the Lewis exhalite. The mineralization in all three ore lenses consists of massive pyrrhotite + chalcopyrite + magnetite. Semi-massive sphalerite is restricted to the upper and lower parts of the Middle lens. Massive magnetite occurs at the center of the Upper and Middle lenses, where it replaces massive pyrrhotite. A striking feature of West Ansil is the presence of abundant colloform and nodular pyrite (+marcasite) in the massive sulphides. Late-stage replacement of massive pyrrhotite by colloform pyrite and marcasite, occurs mostly along the upper and lower contacts of the lenses.

The West Ansil deposit was the first Cu discovery in 25 years in the Noranda Central Camp. It has a combined indicated and inferred resource of ~1.2 Mt. Grades for the indicated resource are 3.4% Cu, 0.4% Zn, 1.4 g/t Au and 9.2 g/t Ag. The bulk of the resource is located in three massive sulphide lenses (Upper, Middle and Lower) that are entirely within the Rusty Ridge Formation above the Lewis exhalite. The mineralization in all three ore lenses consists of massive pyrrhotite + chalcopyrite + magnetite. Semi-massive sphalerite is restricted to the upper and lower parts of the Middle lens. Massive magnetite occurs at the center of the Upper and Middle lenses, where it replaces massive pyrrhotite. A striking feature of West Ansil is the presence of abundant colloform and nodular pyrite (+marcasite) in the massive sulphides. Late-stage replacement of massive pyrrhotite by colloform pyrite and marcasite, occurs mostly along the upper and lower contacts of the lenses.

The giant Kidd Creek Mine is an Archean Cu-Zn-Ag deposit in the Abitibi Greenstone belt, located in the Superior Province of Canada and is one of the largest known base metal massive sulfide mines in the world with a tonnage of 170.7 Mt (Past production, Resource and Reserve). The massive sulfides in Mine D comprise a number of ore lenses that are interpreted to be the downplunge continuation of the Central orebody from the upper mine. These are referred to as the West, Main, and South lenses. The massive sulfides overlie a silicified rhyolitic unit at the top of a mixed assemblage of rhyolite flows, volcaniclastic sediments and ultramafic flows. The sheared nature of the fragmental units in the hanging wall of the deposit, at depth, illustrates the greater deformation that has occurred than in the upper mine. Metal zonation and the distribution of Cu stringer mineralization suggest that the West and Main lenses may be part of a single massive sulfide body (Main orebody) that has been structurally dismembered. The South Lens is a detached body, separated by late faults. The large Cu stringer zone beneath the West and Main lenses has a thickness of up to 150 metres, and is much broader and structurally remobilized in Mine D partially due to a newly identified series of vertically trending offset faults, that extends along the entire length of the massive sulfide bodies. A number of features of the North, Central and South orebodies in the upper part of the mine (e.g., Se-rich halo around Cu-rich zones) have been recognized in Mine D and provide an important framework for correlating the deep orebodies with the upper levels of the mine. Drilling below the current mine levels indicates that the massive sulfide and Cu stringer zones continue below 10,200 feet (3109 m) and highlight the remarkable continuity of the deposit downplunge with no end in sight. Two main ore suites have been recognized in the upper part of the mine and in Mine D: a low-temperature, polymetallic assemblage of Zn, Ag, Pb, Cd, Sn, Sb, As, Hg, ±Tl, ±W, and a higher-temperature suite of Cu, Co, As, Bi, Se, In, ±Ni. More than 25 different ore minerals and ore-related gangue minerals are present, including Co-As-sulfides, Cu-Sn-sulfides, Ag-minerals, and selenides. The massive ores consist mainly of pyrite, pyrrhotite, sphalerite, magnetite and chalcopyrite, together with minor galena, tetrahedrite, arsenopyrite, and native silver with a quartz and siderite gangue. Despite the high Ag content of the ores, the majority of the massive sulfides are remarkably Au poor except for a local gold zone that has been recognized in the deep mine in association with high-temperature mineralization. The trace elements in the ores exhibit strong zonation and diverse mineralogy. Spectacular albite porphyroblasts, up to 1 cm in size occur in the most Cu-rich ores of Mine D which are coincident with the peak of regional metamorphism and likely represent higher metamorphic or hydrothermal temperatures. Overall the orebodies have remained remarkably similar downplunge. However, unlike the upper part of the mine, pyrrhotite is dominantly hexagonal, only tetrahedrite was observed as the dominant sulfosalt, and magnetite occurs as both blebby porphyroblasts and as abundant intergrowths with sphalerite-chalcopyrite ores and siderite. These characteristics suggest that the deep mine has been subjected to higher metamorphic temperatures, possibly related to depth of burial, and that the original hydrothermal fluids may of had a lower H2S/CO2 and/or higher temperatures.

The West Ansil deposit was the first Cu discovery in 25 years in the Noranda Central Camp. It has a combined indicated and inferred resource of ~1.2 Mt. Grades for the indicated resource are 3.4% Cu, 0.4% Zn, 1.4 g/t Au and 9.2 g/t Ag. The bulk of the resource is located in three massive sulphide lenses (Upper, Middle and Lower) that are entirely within the Rusty Ridge Formation above the Lewis exhalite. The mineralization in all three ore lenses consists of massive pyrrhotite + chalcopyrite + magnetite. Semi-massive sphalerite is restricted to the upper and lower parts of the Middle lens. Massive magnetite occurs at the center of the Upper and Middle lenses, where it replaces massive pyrrhotite. A striking feature of West Ansil is the presence of abundant colloform and nodular pyrite (+marcasite) in the massive sulphides. Late-stage replacement of massive pyrrhotite by colloform pyrite and marcasite, occurs mostly along the upper and lower contacts of the lenses.

The giant Kidd Creek Mine is an Archean Cu-Zn-Ag deposit in the Abitibi Greenstone belt, located in the Superior Province of Canada and is one of the largest known base metal massive sulfide mines in the world with a tonnage of 170.7 Mt (Past production, Resource and Reserve). The massive sulfides in Mine D comprise a number of ore lenses that are interpreted to be the downplunge continuation of the Central orebody from the upper mine. These are referred to as the West, Main, and South lenses. The massive sulfides overlie a silicified rhyolitic unit at the top of a mixed assemblage of rhyolite flows, volcaniclastic sediments and ultramafic flows. The sheared nature of the fragmental units in the hanging wall of the deposit, at depth, illustrates the greater deformation that has occurred than in the upper mine. Metal zonation and the distribution of Cu stringer mineralization suggest that the West and Main lenses may be part of a single massive sulfide body (Main orebody) that has been structurally dismembered. The South Lens is a detached body, separated by late faults. The large Cu stringer zone beneath the West and Main lenses has a thickness of up to 150 metres, and is much broader and structurally remobilized in Mine D partially due to a newly identified series of vertically trending offset faults, that extends along the entire length of the massive sulfide bodies. A number of features of the North, Central and South orebodies in the upper part of the mine (e.g., Se-rich halo around Cu-rich zones) have been recognized in Mine D and provide an important framework for correlating the deep orebodies with the upper levels of the mine. Drilling below the current mine levels indicates that the massive sulfide and Cu stringer zones continue below 10,200 feet (3109 m) and highlight the remarkable continuity of the deposit downplunge with no end in sight. Two main ore suites have been recognized in the upper part of the mine and in Mine D: a low-temperature, polymetallic assemblage of Zn, Ag, Pb, Cd, Sn, Sb, As, Hg, ±Tl, ±W, and a higher-temperature suite of Cu, Co, As, Bi, Se, In, ±Ni. More than 25 different ore minerals and ore-related gangue minerals are present, including Co-As-sulfides, Cu-Sn-sulfides, Ag-minerals, and selenides. The massive ores consist mainly of pyrite, pyrrhotite, sphalerite, magnetite and chalcopyrite, together with minor galena, tetrahedrite, arsenopyrite, and native silver with a quartz and siderite gangue. Despite the high Ag content of the ores, the majority of the massive sulfides are remarkably Au poor except for a local gold zone that has been recognized in the deep mine in association with high-temperature mineralization. The trace elements in the ores exhibit strong zonation and diverse mineralogy. Spectacular albite porphyroblasts, up to 1 cm in size occur in the most Cu-rich ores of Mine D which are coincident with the peak of regional metamorphism and likely represent higher metamorphic or hydrothermal temperatures. Overall the orebodies have remained remarkably similar downplunge. However, unlike the upper part of the mine, pyrrhotite is dominantly hexagonal, only tetrahedrite was observed as the dominant sulfosalt, and magnetite occurs as both blebby porphyroblasts and as abundant intergrowths with sphalerite-chalcopyrite ores and siderite. These characteristics suggest that the deep mine has been subjected to higher metamorphic temperatures, possibly related to depth of burial, and that the original hydrothermal fluids may of had a lower H2S/CO2 and/or higher temperatures.

Massive sulfide deposits in the Noranda mining camp, northwestern Québec, are mainly associated with extensive footwall alteration defined by intense chloritization and sericitization. However, Fe-carbonate alteration also occurs in proximity to some deposits. To test the exploration significance of carbonate alteration in the camp, two areas of intense carbonate alteration were examined, around the small Delbridge deposit and near the new Pinkos occurrence in the Cyprus Rhyolite. Between 1969 and 1971, the Delbridge deposit produced 370,000 t of ore grading 9.6% Zn, 0.61% Cu, 110 g/t Ag, and 2.1 g/t Au. Recent drilling at the new Pinkos occurrence intersected 2.64 m of massive to semi-massive sulfides grading 8.1% Zn and 18.2 g/t Ag. Alteration mapping has shown that the distribution of Fe-carbonates can be used to identify vertically extensive zones of hydrothermal upflow at both properties. At Delbridge, intense Fe-carbonate alteration in brecciated rhyolite defines a pipe-like upflow zone that extends vertically for up to 300 m within the stratigraphic footwall of the massive sulfides and 100 m into the hanging wall. The location of known massive sulfide mineralization coincides with the intersection of the alteration pipe and a favorable horizon marked by the occurrence of fine-grained volcaniclastic rocks. At Pinkos, a similar zone of Fe-carbonate alteration occurs in outcrops of coherent rhyolite. Fe-carbonate alteration is most intensely developed along polygonal cooling fractures in massive rhyolite and decreases in intensity towards the centers of the columns. Fe-carbonate stringers and locally abundant matrix carbonate occur in fragmental rocks at the stratigraphic top of the coherent rhyolite flows and are most intense at the location of sulfide-bearing outcrops that mark the known mineralized horizon. Whereas Fe-carbonate alteration defines the central part of the hydrothermal upflow zones at both properties, disseminated pyrite occurs at the margins and is widespread outside the main upflow zones. This may indicate that Fe-carbonate in the main upflow zones formed at the expense of earlier disseminated sulfides. Replacement of pyrite by synvolcanic Fe-carbonate alteration at Delbridge and Pinkos can probably be attributed to a relatively high concentration of dissolved CO2, possibly of magmatic origin, in the main-stage ore-forming fluids.

Massive sulfide deposits in the Noranda mining camp, northwestern Québec, are mainly associated with extensive footwall alteration defined by intense chloritization and sericitization. However, Fe-carbonate alteration also occurs in proximity to some deposits. To test the exploration significance of carbonate alteration in the camp, two areas of intense carbonate alteration were examined, around the small Delbridge deposit and near the new Pinkos occurrence in the Cyprus Rhyolite. Between 1969 and 1971, the Delbridge deposit produced 370,000 t of ore grading 9.6% Zn, 0.61% Cu, 110 g/t Ag, and 2.1 g/t Au. Recent drilling at the new Pinkos occurrence intersected 2.64 m of massive to semi-massive sulfides grading 8.1% Zn and 18.2 g/t Ag. Alteration mapping has shown that the distribution of Fe-carbonates can be used to identify vertically extensive zones of hydrothermal upflow at both properties. At Delbridge, intense Fe-carbonate alteration in brecciated rhyolite defines a pipe-like upflow zone that extends vertically for up to 300 m within the stratigraphic footwall of the massive sulfides and 100 m into the hanging wall. The location of known massive sulfide mineralization coincides with the intersection of the alteration pipe and a favorable horizon marked by the occurrence of fine-grained volcaniclastic rocks. At Pinkos, a similar zone of Fe-carbonate alteration occurs in outcrops of coherent rhyolite. Fe-carbonate alteration is most intensely developed along polygonal cooling fractures in massive rhyolite and decreases in intensity towards the centers of the columns. Fe-carbonate stringers and locally abundant matrix carbonate occur in fragmental rocks at the stratigraphic top of the coherent rhyolite flows and are most intense at the location of sulfide-bearing outcrops that mark the known mineralized horizon. Whereas Fe-carbonate alteration defines the central part of the hydrothermal upflow zones at both properties, disseminated pyrite occurs at the margins and is widespread outside the main upflow zones. This may indicate that Fe-carbonate in the main upflow zones formed at the expense of earlier disseminated sulfides. Replacement of pyrite by synvolcanic Fe-carbonate alteration at Delbridge and Pinkos can probably be attributed to a relatively high concentration of dissolved CO2, possibly of magmatic origin, in the main-stage ore-forming fluids.

Massive sulfide deposits in the Noranda mining camp, northwestern Québec, are mainly associated with extensive footwall alteration defined by intense chloritization and sericitization. However, Fe-carbonate alteration also occurs in proximity to some deposits. To test the exploration significance of carbonate alteration in the camp, two areas of intense carbonate alteration were examined, around the small Delbridge deposit and near the new Pinkos occurrence in the Cyprus Rhyolite. Between 1969 and 1971, the Delbridge deposit produced 370,000 t of ore grading 9.6% Zn, 0.61% Cu, 110 g/t Ag, and 2.1 g/t Au. Recent drilling at the new Pinkos occurrence intersected 2.64 m of massive to semi-massive sulfides grading 8.1% Zn and 18.2 g/t Ag. Alteration mapping has shown that the distribution of Fe-carbonates can be used to identify vertically extensive zones of hydrothermal upflow at both properties. At Delbridge, intense Fe-carbonate alteration in brecciated rhyolite defines a pipe-like upflow zone that extends vertically for up to 300 m within the stratigraphic footwall of the massive sulfides and 100 m into the hanging wall. The location of known massive sulfide mineralization coincides with the intersection of the alteration pipe and a favorable horizon marked by the occurrence of fine-grained volcaniclastic rocks. At Pinkos, a similar zone of Fe-carbonate alteration occurs in outcrops of coherent rhyolite. Fe-carbonate alteration is most intensely developed along polygonal cooling fractures in massive rhyolite and decreases in intensity towards the centers of the columns. Fe-carbonate stringers and locally abundant matrix carbonate occur in fragmental rocks at the stratigraphic top of the coherent rhyolite flows and are most intense at the location of sulfide-bearing outcrops that mark the known mineralized horizon. Whereas Fe-carbonate alteration defines the central part of the hydrothermal upflow zones at both properties, disseminated pyrite occurs at the margins and is widespread outside the main upflow zones. This may indicate that Fe-carbonate in the main upflow zones formed at the expense of earlier disseminated sulfides. Replacement of pyrite by synvolcanic Fe-carbonate alteration at Delbridge and Pinkos can probably be attributed to a relatively high concentration of dissolved CO2, possibly of magmatic origin, in the main-stage ore-forming fluids.