This division includes all establishments primarily engaged in mining. Mining is used in the broad sense to include the extraction of minerals occurring naturally: solids, such as coal and ores; liquids, such as crude petroleum; and gases, such as natural gas. The term "mining" is also used in the broad sense to include quarrying, well operation, milling and other preparation customarily done at the mine site, or as a part of mining activity. Exploration and development of mineral properties are included. Services performed on a contract, fee or similar basis in the development or operation of mineral properties are classified separately but within this division. Establishments which have complete responsibility for operating mines, quarries or oil and gas wells for others on a contract, fee or similar basis are classified according to the product mined rather than as mineral services. Mining operations are classified, by industry, on the basis of the principal mineral produced or, if there is no production, on the basis of the principal mineral for which exploration or development work is in progress. (Prior code § 11-20-008)