21 Mining, Quarrying, and Oil and Gas Extraction

Industries in the Oil and Gas Extraction subsector operate and/or develop oil and gas field properties. Operation and development activities include exploration for crude petroleum and natural gas; drilling, completing, and equipping wells; operating separators, emulsion breakers, desilting equipment, and field gathering lines for crude petroleum and natural gas; and all other activities in the preparation of oil and gas up to the point of shipment from the producing property. This subsector includes the production of crude petroleum, the mining and extraction of oil from oil shale and oil sands, the production of natural gas, sulfur recovery from natural gas, and recovery of hydrocarbon liquids. Establishments in this subsector include those that operate oil and gas wells on their own account or for others on a contract or fee basis. Establishments primarily engaged in providing support services, on a contract or fee basis, required for the drilling or operation of oil and gas wells (except geophysical surveying and mapping, mine site preparation, construction of oil/gas pipelines, and transportation activities) are classified in Subsector 213, Support Activities for Mining.

Industries in the Mining (except Oil and Gas) subsector primarily engage in mining, mine site development, and beneficiating (i.e., preparing) metallic minerals and nonmetallic minerals, including coal. The term "mining" is used in the broad sense to include ore extraction, quarrying, and beneficiating (e.g., crushing, screening, washing, sizing, concentrating, and flotation), customarily done at the mine site. Beneficiation is the process whereby the extracted material is reduced to particles which can be separated into mineral and waste, the former suitable for further processing or direct use. The operations that take place in beneficiation are primarily mechanical, such as grinding, washing, magnetic separation, centrifugal separation, and so on. In contrast, manufacturing operations primarily use chemical and electrochemical processes, such as electrolysis, distillation, and so on. However, some treatments, such as heat treatments, take place in both stages: the beneficiation and the manufacturing (i.e., smelting/refining) stages. The range of preparation activities varies by mineral and the purity of any given ore deposit. While some minerals, such as petroleum and natural gas, require little or no preparation, others are washed and screened, while yet others, such as gold and silver, can be transformed into bullion before leaving the mine site. Establishments in the Mining (except Oil and Gas) subsector include those that have complete responsibility for operating mines and quarries (except oil and gas wells) and those that operate mines and quarries (except oil and gas wells) for others on a contract or fee basis. Establishments primarily engaged in providing support services, on a contract or fee basis (except geophysical surveying and mapping, mine site preparation, construction, and transportation activities), required for the mining and quarrying of minerals are classified in Subsector 213, Support Activities for Mining.

Industries in the Support Activities for Mining subsector group establishments primarily providing support services, on a contract or fee basis (except geophysical surveying and mapping, mine site preparation, construction, and transportation activities), required for the mining and quarrying of minerals and for the extraction of oil and gas. Establishments performing exploration for minerals, on a contract or fee basis, are included in this subsector. Exploration services include traditional prospecting methods, such as taking core samples and making geological observations at prospective sites. The activities performed on a contract or fee basis by establishments in the Support Activities for Mining subsector are also often performed in-house by mining operators. These activities include taking core samples, making geological observations at prospective sites, excavating slush pits and cellars, and such oil and gas operations as spudding in, drilling in, redrilling, directional drilling, and well surveying; running, cutting, and pulling casings, tubes, and rods; cementing and shooting wells; perforating well casings; acidizing and chemically treating wells; cleaning out, bailing, and swabbing wells; and operating oil and gas field gathering lines. Establishments primarily engaged in providing site preparation and related construction activities on a contract or fee basis are classified in Sector 23, Construction. Establishments primarily engaged in providing transportation activities in support of mining, quarrying, or oil and gas extraction are classified in Sector 48-49, Transportation and Warehousing, based on the primary activity.