Porphyries13 Dec 2018 18:34
FOUR THINGS TO KNOW ON PORPHYRIES
Polymetallic nature – Each porphyry is unique and holds different concentrations of minerals. Some deposits have such high concentrations of gold that they may be considered gold deposits rather than copper deposits. Others have barely any gold at all but may have plenty of molybdenum.
Large Size, Low Grade – Porphyries typically have 100 million to 5 billion tonnes of ore with a lower grade (0.2% to >1% copper). It is the size of these deposits that allow for bulk mining and economies of scale.
Long Mine Life – The size of porphyry systems usually mean that the life of the mine can be multi-decades long. This means that these deposits last through multiple market cycles, and are thus not as vulnerable to challenging market environments compared to other smaller mines.
Infrastructure is Key – In order to process large amounts of ore, infrastructure can be a large part of initial capital expenditures (CAPEX). Access to power and water are key issues as large amounts of both are needed to process ore. The footprint of the mine and volume of tailings disposal can also make porphyries more challenging to permit.
EXAMPLE PORPHYRY
Each year the Bingham Canyon Mine, located in Utah and owned by Rio Tinto and in production since 1906, produces approximately:
300,000 tons of copper
400,000 oz of gold
4,000,000 oz of silver
30,000,000 lbs of molybdenum
The value of the resources extracted to date from the Bingham Canyon Mine is greater than the Comstock Lode, Klondike, and California gold rush mining regions combined.
Sign In
Follow the stocks
