37 Drilling and pumping of wells; drilling of crude oil; drilling of hydrocarbons; oil pumping and extraction; oil and gas drilling; mining extraction; exploitation and extraction of oil and gas; repair services for machines in the oil and gas industries; pipeline construction and maintenance; oil and gas pipeline inspection, maintenance and repair services; repair and maintenance of pumps; installation, maintenance and repair services, all relating to equipment and machines for use in fluids management, solid control, production waste management machines, filtration and screening machines, machines for completion services, machines for cleaning and purifying environments and environmental clean-up in the oil, coal and gas and environmental industries sectors; installation, maintenance and repair services, all relating to equipment and machines for use in the separation of solids from liquids, liquids from solids and liquids from liquids, all through mechanically or chemically enhanced means in the oil, coal and gas and environmental industries; installation, maintenance and repair services for equipment and apparatus in the oil, coal and gas and mining industries, including pipelines, drill pipes, tubing, casing, line pipes, and other tubular goods and accessories; threading services in the oil, coal and gas and ecological industries; construction of structures for the transportation and storage of oil and gas; laying, repair, maintenance, replacement, refurbishment of pipelines; repair and maintenance of gas installations; rental, installation and maintenance of oil and gas well drilling tools; rental, installation and maintenance of cleaning machines, including high pressure washing and machines for cleaning sewers, containers and drill holes, slurry treating machines, all for the oil, coal and gas and ecological industries; rental of treatment, cleaning and purification machines for use in the oil, coal and gas and ecological industries; rental of solids control machines, production waste management machines, filtration and screening machines and machines for completion services, all for the oil, coal and gas industries; construction and supervision of subcontractors; technical supervision of building and construction projects; installation of electricity generators; installation of apparatus for gathering of fuel, natural gas, coal and oil; building and construction of electrical power plants; rental of mining equipment