Ore
Rock or mineral material containing a metal or mineral in enough quantity and grade that it can be mined and processed at a profit.
Detailed Definition
Ore is rock or mineral material that can be mined and processed at a profit. the U.S. Bureau of Mines' Dictionary of Mining, Mineral, and Related Terms (1968) defines it as "a mineral of sufficient value as to quality and quantity which may be mined with profit," and as a mineral or aggregate containing useful metals that "occurs in such quantity, grade, and chemical combination as to make extraction commercially profitable."
Ore is an economic term
Whether rock is ore depends on the price of the metal, the cost of mining and processing, and the grade and size of the deposit, not on the rock alone. Material that is waste at one price can be ore at another. That is why a deposit is described by grade and tonnage, and why the cut-off grade separates ore from waste.
How the SEC handles it
The SEC's mining disclosure rules (Regulation S-K subpart 1300, 17 CFR 229.1300) do not use the word "ore" at all. They classify material as:
- Mineral resource: a concentration of material "in such form, grade or quality, and quantity that there are reasonable prospects for economic extraction"
- Mineral reserve: "the economically mineable part of a measured or indicated mineral resource," including dilution and allowances for losses in mining
A public company's statement of what it can mine at a profit is its mineral reserve.
How BLM uses the word
BLM's surface management rules use "ore" in its ordinary sense. For example, a plan of operations is required for "any bulk sampling in which you will remove 1,000 tons or more of presumed ore for testing" (43 CFR 3809.11(b)).
Ore, grade, and tailings
- Grade is the concentration of the metal or mineral in the rock.
- Beneficiation prepares ore by crushing, grinding, and concentrating it.
- Tailings are what remains after the valuable part is extracted.
- Waste rock is material removed to reach the ore and never processed.
Why it matters for mining claims
A mining claim rests on the discovery of a valuable mineral deposit. Whether a deposit is valuable enough is decided on the same economic logic as whether rock is ore: what it contains, what it would cost to extract, and what it would sell for. Sampling, assays, and grade estimates are the evidence for both.
Related Terms
Mineral Resource
A concentration of material of economic interest in such form, grade, and quantity that there are reasonable prospects for economic extraction, classed as inferred, indicated, or measured.
Mineral Reserve
The economically mineable part of a measured or indicated mineral resource, including diluting materials and allowances for losses, classed as probable or proven.
Grade
The concentration of a metal or mineral in rock, such as ounces of gold per ton or percent copper, which together with tonnage decides whether a deposit can be mined at a profit.
Tailings
The finely ground material left over after the valuable metal or mineral has been extracted from ore, usually stored in an impoundment or pile.
Beneficiation
The preparation of ore to control its size, remove unwanted material, or raise its grade, by steps such as crushing, grinding, flotation, gravity or magnetic concentration, and leaching.
Stripping Ratio
In surface mining, the amount of waste rock or overburden that must be removed to reach a unit of ore, such as 3 tons of waste for each ton of ore.