| Shaft type | Soviet Union | 1932-1965 | Lisichansk,
Yuzno-Abinsk,
Podmoskova,
Shatskaya | 20-40 | Sub-bitumi-
nous coal
and lignite | 0.4-2.0 | Used for power generation or fuel for manufacturing industry. Due to the discovery of large amount of oil and natural gas resources, most UCG projects were stopped during the 1960s |
| 1961 to now | Angrenskaja | 110-126 | Lignite | 9.0 | Since 1961 to now, with simple process and mature technology, it produces 100×108 m3 of gas every day for power station |
| China | 1958-2010 | Ezhuang in Xinwen, Xinhe in Xuzhou, Liuzhuang in Tangshan and Huating in Gansu, etc. | 80-200 | Gas-fat coal,
gas coal and non-caking coal | 1.2-9.0 | Gasification scale is small, and the caloric value of produced gas is low to medium |
| Drilling type | Soviet Union | 1955-1991 | Yuzhno-Abinsk | 43-53 | Bituminous
coal | 9.2-9.8 | Dip angle of coal bed was 70° and SDB (Steeply Dipping Coal Bed) was adopted for gasification. It was stopped due to surface depression and collapse of the Soviet Union, etc. |
| US | 1973-1979 | Hanna series tests | 84-114 | Class-C high volatile bituminous coal | 9.0 | O2 and CO2 corroded the pipe columns of the producing well and caused failure of the project |
| 1976-1979 | Hoe Creek | 40 | Class-C high volatile bituminous coal | 8.0 | To solve the problems such as puking, air leakage and water inflow, CRIP (Controlled Retraction Injection Point) was developed |
| 1987-1988 | Rocky Mountain I | 110 | Sub-bitumi-
nous coal | 7.0 | The test was the largest in the US, which improved productivity and caloric value, enlarged the furnace type and reduced the cost. The project was stopped due to surface depression and shallow water pollution |
| France | 1979-1981 | Bruayen Artois | 1 170 | Bituminous
coal | 1.2-1.5 | Reverse combustion after hydraulic fracturing was adopted for connection. The test failed due to poor connection effect |
| Belgium | 1979-1988 | Thulin | 860 | Bituminous
coal | 6.0 | Connection process by reverse combustion failed. Directional well was adopted afterwards and connection succeeded |
| China | 1987 | Mazhuang in Xuzhou | 82 | Gas-fat
coal | 1.2 | Coal bed was thin and shaft-less gasification was tested, with low caloric value of produced gas |
| Spain | 1991-1999 | Tremedal test | 500-700 | Sub-bitumi-
nous coal | 2.0 | It proved the feasibility of medium-deep UCG, but due to imperfect geological conditions, water rushed into the gasification cavity, leading to combustion failure |
| South Africa | 2007-2011 | Majuba test | 250-380 | Sub-bitumi-
nous coal | 3.5 | Small-scale test was carried out, with low caloric value of produced gas; follow-up commercialization project wasn’t carried out due to national policies |
| Canada | 2007-2012 | Swanhills test | 1 400 | High volatile
bituminous coal | 4.5 | It proved the theory that the methane content increases as the pressure increases, but was stopped due to the burning accident of coiled tubing |
| Australia | 2011-2013 | Chinchilla 5 test | 130 | Sub-bitumi-
nous coal | 5.5 | Gasification space was 300 m and the project ran stably for 24 months, but was stopped due to national environmental protection policies |
| China | 2007-2012 | Ulanqab test | 285 | Lignite | 6.0 | It succeeded for a period of time in the early stage, but was stopped due to technical troubles in coiled tubing and low conversion rate of combustible gas |