In the farm-oriented economy of the early 19th century, the need for mineral statistics for setting government policy, except for tariffs and taxes, was slight. The only sources of information on the mining sector were the censuses of mineral industries, then taken at 10-year intervals. Today, the need for mining statistics has greatly increased so there is now a vast array of detailed information covering virtually every measurable aspect of mining activity including employment; payrolls; hours worked; production; prices; inventories; investment in structures; machinery and equipment; and consumption of raw materials, and fuels. The census of mineral industries, though conducted only at 5-year intervals, still plays an essential role, since no other source measures the structure of the mining sector in such a comprehensive and detailed way.

For every mining establishment with one employee or more, the census obtains data on its input of labor, materials, and capital; its output of products and services; its location; and the legal form of organization of the owning firm.

A set of summary or general statistics is developed for each establishment (i.e., total employment, payroll, productionworker employment, hours worked, wages, cost of supplies, value of shipments and receipts, capital expenditures, and value added by mining) and aggregated by industry, by area, by employment size of establishment, and by type of ownership. Reports are published on the detailed industrial characteristics of each State, and overall measures of mining activity are shown at the county level provided the information can be published without compromising the confidentiality of individual company data. Since census legislation guarantees confidentiality to the firms that are required to report, it is frequently necessary to suppress some aggregates.