bamboo derricks and then were repeatedly raised and dropped into a manually dug hole by having two to six men jumping on a lever. Han dynasty oil wells made by percussion drilling was effective but only reached 10 meters deep and 100 meters by the 10th century. By the 16th century, the Chinese were exploring and drilling oil wells more than deep. Chinese well drilling technology was introduced to Europe in 1828. A modernized variant of the ancient Chinese drilling technique was used by American businessman Edwin Drake to drill Pennsylvania's first oil well in 1859 using small steam engines to power the drilling process rather than by human muscle.Cable tool drilling was developed in ancient China and was used for drilling brine wells. The salt domes also held natural gas, which some wells produced and which was used for evaporation of the brine. Drake learned of cable tool drilling from Chinese laborers in the U. S. The first primary product was kerosene for lamps and heaters. Similar developments around Baku fed the European market. In the 1970s, outside of the oil and gas industry, roller bits using mud circulation were replaced by the first pneumatic reciprocating piston Reverse Circulation (RC) drills, and became essentially obsolete for most shallow drilling, and are now only used in certain situations where rocks preclude other methods. RC drilling proved much faster and more efficient, and continues to improve with better metallurgy, deriving harder, more durable bits, and compressors delivering higher air pressures at higher volumes, enabling deeper and faster penetration. Diamond drilling has remained essentially unchanged since its inception. Petroleum drilling industry Oil and natural gas drilling rigs are used not only to identify geologic reservoirs, but also used to create holes that allow the extraction of oil or natural gas from those reservoirs. Primarily in onshore oil and gas fields once a well has been drilled, the drilling rig will be moved off of the well and a service rig (a smaller rig) that is purpose-built for completions will be moved on to the well to get the well on line. This frees up the drilling rig to drill another hole and streamlines the operation as well as allowing for specialization of certain services, i.e. completions vs. drilling. Mining drilling industry Mining drilling rigs are used for two main purposes, exploration drilling which aims to identify the location and quality of a