Which statement defines an ore?
A. Rock broken down to become part of the topsoil
B. Rock dug out from the earth to use in construction.
C. Rock dug out from the deep inside earth and refined
D. Rock exposed as a result of loss of topsoil.
The Correct Answer and Explanation is:
The correct answer is C. Rock dug out from the deep inside earth and refined.
Explanation
An ore is a type of rock that contains sufficient minerals with economically important elements, typically metals, that can be extracted from the rock. The extraction process usually involves mining the ore from deep underground or from the surface, depending on its location. Once the ore is obtained, it undergoes refining processes to separate the valuable metals from the surrounding materials, known as gangue. This refining can include various physical and chemical methods such as crushing, grinding, and smelting.
Ores are crucial for the production of metals used in a wide range of applications. For instance, iron ore is primarily used to produce iron and steel, while copper ore is refined to obtain copper for electrical wiring and plumbing. The economic value of ores lies in their concentration of useful metals. The grade of an ore, which refers to the proportion of the desired metal within it, determines how economically viable it is to extract and refine that metal. Higher-grade ores contain more of the valuable metal, making the extraction process more profitable.
In contrast to the other options, definitions A, B, and D do not accurately capture the essence of what an ore is. Option A refers to the role of rock in soil formation but does not relate to the economic value associated with ores. Option B describes general construction materials, which can include non-ore rocks, while option D highlights erosion processes rather than the intrinsic value of ores. Therefore, option C is the most accurate and encompasses the full definition of an ore, emphasizing its extraction and refinement for economic use.