Abstract: A series of specialty formulations of foaming mud cement are injected into an underground cavity containing an active coal fire. The fire is smothered and terminated with a blanket of foaming mud cement that sets into a cellular concrete. The lower section of the backfill involves a formulation of foaming mud cement containing materials conducive to heat transfer, thus forming a heat sink for dispersion of elevated temperature associated with the fire. The backfill continues to complete cavity fill using a formulation of foaming mud cement wherein the aggregate is composed of hazardous waste materials that are permanently stored within the cellular concrete.

Abstract: Production of methane from an underground wet coal seam is initiated by drilling a well from the surface of the earth through the seam. Rather than pumping water to lower hydraulic head on the seam to permit desorption of methane within the coal, high pressure gas is injected into the seam to drive water away from the wellbore. Gas injection is terminated and the well is opened to flow. Initial gas production is return of injected gas, followed by a mixture of return injected gas and methane, followed by free methane from the fracture system of the coal, and then by methane desorbed from the coal. Upon return of displaced water to the wellbore, pumping operations remove water at rates that permit sustained production of desorbed methane.

Abstract: After a linkage channel is established through an underground coal seam connecting two vertical wells, a tubing bender/straightener is positioned in a first well aligned with the linkage channel. Oxidizer injection tubing is inserted from the wellhead into the tubing bender/straightener. The tubing is forced through the tubing bender/straightener and on into the linkage channel. The coal is ignited and the fire sustained by continuous injection of oxidizer through the tubing, creating a reaction zone separated from the first well with products of reaction recovered through the second well.

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: The system of the invention comprises a two well system of gasifying coal in situ wherein the generated gas stream is directed to a gas separator, which, in turn separates hydrogen and carbon monoxide into separate streams. Hydrogen is directed to one type of fuel cell and carbon dioxide is directed to another with the resultant generation of electricity.The method of the invention comprises establishing two wells into an underground coal deposit with a reaction zone in fluid communication with the wells. Coal is gasified both in oxidizing and reducing environments, with the produced gas stream separated into its component parts. Combustible gases are directed to fuel cells with the resultant generation of electricity.

Abstract: Heavy oil from underground oil sands or tar sands is liquified with recirculation of superheated water and when brought to the ground surface is then wet oxidized for its heat value. The sulphur content of the products of wet oxidation is then wet reduced to elemental sulphur for by-product. The carbon dioxide gas generated as a product of wet oxidation is injected back to wells for its value as a diluter of the oil. Heat produced from wet oxidation is used for useful work at wells site.

Abstract: A reactor vessel is established wherein a fuel is oxidized within an inert oxygen-carrier liquid. A portion of the heat of oxidation is used to raise steam. In one embodiment a double acting engine is interconnected to the reactor vessel wherein the first stroke of the piston is actuated by exhaust gases from the products of oxidation and the return stroke of the piston is actuated by the said steam. In other embodiments generated gases are used to power a turbine and a gas lift pump.

Abstract: Reactor pressure vessel with reactant fluid injectors for forming a liquid environment of an oxygen carrier fluid, sulphur and water in the presence of a catalyst to yield sulphuric acid and heat exchangers to capture generated heat.

Abstract: In preparation for producing coal in situ two or more production wells are linked together through the coal seam by burned channels created by one or more blind hole burns.

Abstract: Stack gases derived from combustion of hydrocarbons are scrubbed by direct contact with an inert liquid capable of taking sulphur compounds into solution. The inert liquid pregnant with sulphur compounds is injected into a reactor where the sulphur compounds are converted into sulphurous acid or in the presence of a catalyst wet oxidized into sulphuric acid. Product acid is withdrawn from the reactor and the stripped inert liquid is returned to the scrubber to repeat the process. Waste heat is captured for further useful work.

Abstract: Materials with unfulfilled chemical oxygen demand are oxidized in a liquid environment at superatmospheric temperatures and pressures. The liquid environment is created within a pressure vessel by an inert liquid that is capable of absorbing and dispersing oxygen. Generated heat is captured for further useful work.

Abstract: A method for the manufacture of sulphuric acid wherein sulphur, in one case, and a source of sulphur in another case is reacted at superatmospheric temperatures and pressures with oxygen dissolved in an inert liquid in the presence of water, the inert liquid being selected from fluorocarbon compounds having eight or more carbon atoms. Heat is captured from the inert liquid.

Abstract: A water bearing underground coal seam is prepared for production by in situ techniques by drilling a series of wells into the seam. Paths of maximum permeability are determined by taking oriented cores in selected wells. The coal seam is partially dewatered by removing water from the seam in selected wells. Reaction zones are established in the coal, first along the paths of maximum permeability, then reaction zones are established substantially perpendicular to the original paths of maximum permeability.

Abstract: Coal gas is produced in situ using the techniques of gasification, liquefaction and pyrolysis. Normal effluents to the atmosphere are recycled in part to the underground reaction zone for conversion into commercial products. Contaminants to underground aquifers are captured and injected into the underground reaction zone for destruction and transformation into useful products.

Abstract: A previously mined underground coal deposit is sealed so that the underground void space can be pressurized for production by in situ techniques. Excavated communication passages are sealed by barricades which are further sealed by applying hydrostatic head pressure. Subsidence cracks are sealed by injection of mud slurry with additional sealing effected by maintaining hydrostatic head pressure with a column of the slurry. In situ production wells are drilled into the coal with hermetic seal accomplished in part by cementing a portion of the liner to the well bore and in part by the hydrostatic head pressure of a mud slurry positioned above the cement seal. Coal is ignited and burn patterns are established to cause reasonably uniform subsidence.

Abstract: A method of producing combustible gases, synthetic crude oils, coal chemicals and heat from coal in situ utilizes the combined teachings of in situ gasification, liquefaction and pyrolysis.

Abstract: A previously mined underground coal deposit is sealed so that the underground void space can be pressurized for production by in situ techniques. Excavated communication passages are sealed by barricades which are further sealed by applying hydrostatic head pressure. Subsidence cracks are sealed by injection of mud slurry with additional sealing effected by maintaining hydrostatic head pressure with a column of the slurry. In situ production wells are drilled into the coal with hermetic seal accomplished in part by cementing a portion of the liner to the well bore and in part by the hydrostatic head pressure of a mud slurry positioned above the cement seal. Coal is ignited and burn patterns are established to cause reasonably uniform subsidence.

Abstract: A well is drilled from the surface of the earth into an underground coal formation. The coal seam is fractured by fluids injected under pressure. Methane entrained in the cracks and fissures is removed to surface facilities. Coal seam in the vicinity of well bore is partially dewatered. Diameter of well bore in the coal section is enlarged first by underreaming the hole, then by a vertical in situ burn to form a collection chimney. Methane desorbed from the coal is withdrawn to surface facilities.