Goldstrike mineralization is best described to be in the class of sedimentary rock-hosted Carlin-style deposits. The Carlin-style class of gold deposits are not unique to the eastern Great Basin. They are characterized by concentrations of very finely disseminated gold in silty, carbonaceous, and calcareous rocks. The gold is present as micron-size to sub-micron-size disseminated grains, often internal to iron-sulphide minerals (arsenical pyrite is most common) or with carbonaceous material in the host rock. Free particulate gold, and particularly visible free gold, is not a common characteristic of these deposits; significant placer alluvial concentrations of gold are therefore not commonly associated with eroded Carlin-style gold deposits.

All Carlin-style deposits in the Great Basin have some general characteristics in common, although there is a wide spectrum of variants. Anomalous concentrations of arsenic, antimony, and mercury are typically associated with the gold mineralization; thallium, tungsten, and molybdenum may also be present in trace amounts. Alteration of the gold-bearing host rocks of Carlin-type deposits is typically manifested by decalcification, often with the addition of silica, fine-grained disseminated sulphide minerals, remobilization and/or the addition of carbon, and late-stage barite and/or calcite veining. Small amounts of white clays (illite) can also be present. Decalcification of the host produces volume loss, with incipient collaps ........

The PEA Study utilizes open pit mining with mine planning based on economic pit shells generated by mine planning software. Mine production is planned at 22,500 tonnes per day or 8.2 million tonnes per year of leach feed (mineralized) material. With an average waste to leach feed material strip ratio of 1.2 to 1, the average mining rate is approximately 50,000 tonnes per day of leach feed and waste material. The open pit mining at Goldstrike was designed utilizing an owner-operated, conventional mine fleet of front end loaders and trucks.

At the Goldstrike project, stable open pit slopes were developed during previous mining at slope angles of about 50 degrees up to slope heights of 220 m in the Paleozoic rocks where geologic structure orientations are favorable for slope stability. In some of the existing pits, the slopes that appear to have been developed with inter-ramp slopes of 50 degrees became unstable during or after mining. Typically, the unstable slopes in the existing pits are composed of either altered and weathered Tertiary age volcanic rock or Paleozoic rocks containing geologic structures in orientations unfavorable for stability. For the PEA, the existing pits will in some cases be deepened to produce slope heights ranging from 20 to 220 m, and new pits will be developed in areas where there are no existing pits.

The stability of planned open pits was evaluated by comparing the geologic conditions, groundwater and other conditions that r ........

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