Ore grade in the context of "Franke mine"

Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. Ore grade refers to the concentration of the desired material it contains. The value of the metals or minerals a rock contains must be weighed against the cost of extraction to determine whether it is of sufficiently high grade to be worth mining and is therefore considered an ore. A complex ore is one containing more than one valuable mineral.

Minerals of interest are generally oxides, sulfides, silicates, or native metals such as copper or gold. Ore bodies are formed by a variety of geological processes generally referred to as ore genesis and can be classified based on their deposit type. Ore is extracted from the earth through mining and treated or refined, often via smelting, to extract the valuable metals or minerals. Some ores, depending on their composition, may pose threats to health or surrounding ecosystems.

Geostatistics is a branch of statistics focusing on spatial or spatiotemporal datasets. Developed originally to predict probability distributions of ore grades for mining operations, it is currently applied in diverse disciplines including petroleum geology, hydrogeology, hydrology, meteorology, oceanography, geochemistry, geometallurgy, geography, forestry, environmental control, landscape ecology, soil science, and agriculture (esp. in precision farming). Geostatistics is applied in varied branches of geography, particularly those involving the spread of diseases (epidemiology), the practice of commerce and military planning (logistics), and the development of efficient spatial networks. Geostatistical algorithms are incorporated in many places, including geographic information systems (GIS).

A cutoff grade is the minimum grade required in order for a mineral or metal to be economically mined (or processed). Material above this grade is considered to be ore, while material below this grade is considered to be gangue.

The cutoff grade can be determined through a variety of methods, each of varying complexity. Cutoff grades are selected to achieve a certain objective, such as resource utilization or economic benefit. Dividing these objectives even further gives way to specific goals such as the maximization of total profits, immediate profits, and present value. It is important to recognize that the cutoff grade is not simply calculated to a definitive answer. It is in fact a strategic variable that has major implications on mine design. The cutoff grade is adapted as the economic environment changes with regard to metal prices and mining costs, and is therefore constantly changing. Metal value is not the only factor affecting the profitability of an ore block. The presence of unwanted material in an ore block may increase the processing cost. This is also considered when classifying waste rock and ore.

Chile is the world's largest producer of copper and has been so uninterruptedly since 1983. This activity provides a substantial part of the Chilean state's revenue: slightly less than 6% in 2020, with state-owned copper company Codelco alone generating 2.6% of state revenue.

Mining of copper in Chile is done chiefly on large and giant low-grade porphyry copper deposits which are primarily mined by the following companies; Codelco, BHP, Antofagasta Minerals, Anglo American and Glencore. Together these companies stood for 83.6% of the copper output in Chile in 2019 and many copper mining companies are joint ventures involving one at least one of these. Medium-scale mining in Chile, which focuses mainly on copper, produced about 4.5% of the copper mined in the country from 2017 to 2021. Copper is also the main product of small-scale mining in Chile, with about 95% of small-scale miners working in copper mining. One estimate puts the number of active copper mines in Chile in 2023 at 67. In the 2005–2024 period 81–89% of the annual copper production in Chile has been mined in open pits and the remainder in underground mines.