Abstract: The invention relates to a process for separating rock refuse of coal mining and products of coal deposits with rock intercalation, the coal contents of which being advantageously less, than 50%, into parts being rich and poor in coal, respectively, in a given case in a pure refuse parts by using the heavy-media process. In sense of the invention the raw material mentioned above is crushed according to necessity to the grain size of 0 to 50 mm and/or graded. Hereinafter from the raw material and from the weighting material partly being present in the raw material in a quantity of at least 7 weight-%, advantageously 10 weight-%, in a grain size of 0-0.5 mm, partly recycled from the process, a mixture of sludge is prepared in the presence of a liquid phase, while the density of the sludge mixture is adjusted in accordance with the extent of separation. The sludge mixture is allowed to pass through one or more hydrocyclones and equipments separating according to grainsize and/or grading equipments.

Abstract: The mining method of this invention is particularly suitable for the underground extraction of large mineral deposits, wherein a subsidiary road is formed perpendicularly to the work face from which the mineral deposit is to be removed. A boundary subsidiary road is formed substantially perpendicularly to the subsidiary road, a first mine tunnel is formed by removing the mineral deposit from the work face along the subsidiary road until the boundary gate road is reached. Then the material around said first mine tunnel is collapsed to fill the same along the subsidiary road and the collapsed matter is consolidated along the subsidiary road. Finally a second mine tunnel is formed along the subsidiary road. The second mine tunnel can be horizontally or vertically adjacent to the first mine tunnel.

Abstract: The invention relates to a method for recovering rare metals from the combustion residues of various coals, in particular brown coals. The recovery is performed by digestion, more particularly by aqueous and/or dilute alkaline and/or dilute acidic digestion, where two or three of these steps can be combined in any desired order or they may be carried out separately. During digestion the concentration of the solution is monitored and the subsequent digestion steps are terminated at a desired concentration. The solid and liquid phase are then separated and the rare metals are isolated from the liquid phase while the solid phase, optionally after neutralization and/or washing can be utilized for example as a source of energy.

Abstract: A carbonaceous waste product, preferably containing 30 to 60% mineral substances, 35 to 55% carbonaceous materials, 5 to 20% water, and having a calorific value of 2,000 to 3,500 k cal/kg is fired to produce thermal energy and a combustion residue. The residue is adjusted, if necessary, by addition of mineral containing additives so that it contains 15 to 50% alumina, 15 to 20% silica and 13 to 45% other oxides (mainly iron oxide, manganese oxide and calcium oxide). Sufficient limestone is added to produce a mixture containing 1.8 to 2.2 moles of calcium oxide per mole of silica and 1.1 to 1.3 moles of calcium oxide per mole of alumina. The mixture is then sintered. The total energy requirements of the sintering step are supplied by the energy generated in the firing step. Useful products such as cement and cast stone can be produced from the sintered product.

Abstract: The invention relates to an improved method for the production of liquid carbon compounds from coal. According to the invention coal is oxidized at 80.degree. to 300.degree. C. in the presence of the vapors of a C.sub.1-5 aliphatic alcohol, optionally under the introduction of steam, and then the liquid carbon compounds are separated from the resulting product mixture.The process according to the invention can also be performed under atmospheric pressure, 50-80% of the carbon content of the coal converted appear in the liquid product. The liquid product contains the more valuable fraction, boiling below 300.degree. C., as major component.

Abstract: The invention relates to a method for utilizing silicon tetrachloride formed as a by-product of the chlorination of aluminium- and silicon-containing minerals. More particularly, the invention relates to a process for the preparation of aluminium trichloride and silicon dioxide by chlorination of alumina with silicon tetrachloride. According to the invention alumina or a material essentially consisting of alumina is reacted with silicon tetrachloride as a single chlorinating agent at a temperature exceeding 400.degree. C., unreacted silicon tetrachloride is separated from the aluminium trichloride formed and is recycled into the chlorination step, silicon dioxide is isolated from the solid residue essentially consisting of the unreacted alumina and silicon dioxide, unreacted alumina is recycled into the chlorination step and aluminium trichlorine obtained is continuously eliminated.

Abstract: A self-advancing support apparatus for protecting mine gate crossings, and optionally for engaging the reversing/driving head of a longwall and/or gate conveyor. The support apparatus has at least two side by side desired construction but expediently of a construction identical with that of the support unit at the longwall face to which said unit is connected via a coupling element. Each unit includes a base, a canopy, and connected between them, expediently by articulation, bracing elements as well as advancing elements and holding devices mounted on the base, and if so desired, for advancing the reversing/driving head of the longwall conveyor, a guide track extending in the direction of the gate conveyor, and an actuating/controlling unit. A holding mechanism is provided for engaging the reversing/driving head of the longwall conveyor and has at least two degrees of freedom of movement.

Abstract: There is disclosed a process for the extraction of thick coal seams by means of which coal seams not extractable in one bank or slice and/or located at peripheral areas may also be extracted under improved mine safety conditions and with high productivity.According to the invention the thick coal seam is if required, divided horizontally and/or vertically into extraction blocks which are bounded and separated by stowing pillars arranged according to the direction of advance of the extraction. The cavity of the pillars is advanced at a level higher than the level of the roof of the extraction space, after which the cavity of the pillar is back-filled. Then the block is extracted by means of block caving in a manner known per se. In a preferred embodiment of the invention incombustible material that agglomerates under the effect of the static pressure of the rock is used for stowing.The utilization of the process for extraction according to the invention results in a considerable increase of intensity.

Abstract: A process for the underground gasification of coal and carbonaceous materials in makes the customary lengthy preliminary task of establishing an underground interconnection between wells and cavities unnecessary. Instead, according to the invention, the circulation of gasifying agents and product gases is between one or more wells and the boundary of an underground generator (i.e. cavity system) through a reaction zone in the generator.

Abstract: The invention relates to an improved method for the liquid phase oxidation of coal performed with oxygen optionally in the presence of water. According to the invention oxidation is performed in the presence of a cooxidation partner selected from the group of liquid hydrocarbons and oxygen-containing liquid hydrocarbons, and if water is also present, the pH of the homogeneous solution formed from the cooxidation partner and water is maintained at a slightly acidic value.By the method of the invention the formation of carbon dioxide can be suppressed significantly.

Abstract: The invention concerns a process for the preparation of alumina and ferric oxide from low-grade aluminium and iron carriers. The processes, in addition to conventional technological steps, comprises the steps of dissolving the iron content of a ground, mineral material in an aqueous hydrochloric acid solution containing 200 to 420 g./lit. of hydrochloric acid at 90.degree. to 130.degree. C., eliminating the iron from the slurry of from a solution obtained by filtration of the slurry, with an anion exchange resin or semipermeable membrane or cloth, continuously or discontinuously, eluting the iron from the ion exchange resin and recycling hydrochloric acid and sulfuric acid in a closed system.

Abstract: The invention relates to an equipment for the delivery of slurries and for their refinement during delivery, which has a housing provided with axial inlet opening and tangential discharge opening, furthermore a disc-shaped stationary part in the housing with a concentric opening adjoining the inlet opening, and disc-shaped rotary part arranged opposite the stationary part. Rods are concentrically arranged according to the invention alternately on the stationary part and rotary part in such a way, that the rods of the stationary part point toward the rotary part, and the rods of the rotary part point toward the stationary part, and the rotary part has a jacket surrounding the rods arranged along the largest diameter circle of the stationary part, said jacket being perforated with holes in radial direction.

Abstract: In mining a heavy coal seam that must be excavated in several benches, the excavation of the uppermost bench is accompanied by the introduction of a cementitious slurry into the resulting stope for consolidating the waste rock present therein, preparatorily to the excavation of the next-lower bench, and proceeding in like manner with the second bench if a third one is to follow. The cementitious slurry comprises burnt or slaked lime, and/or portland cement, suspended in water in a quantity of about 10 to 60% by weight and preferably together with a small percentage of chlorides of one or more alkali or alkaline-earth metals, to which ceramic aggregates at large specific surface such as mineral ashes, slag, sand or dolomite powder may be added in a quantity of up to about 30% of the weight of the water.

Abstract: A low grade aluminum and silicon containing starting material is intimately mixed with limestone and the resultant mixture is fluidized. The fluidized mixture is preheated to a temperature of 700.degree. to 900.degree. C., then held at sintering temperature for 5 to 10 minutes. Aluminum may be recovered by extraction of the sintered powder so produced.

Abstract: A mixture is prepared from quartz sand, dolomite and/or limestone, sodium carbonate and/or cryolite and having a composition of from about 30 to about 60% SiO.sub.2, from 0 to about 5% Al.sub.2 O.sub.3 from 0 to about 2% FeO+Fe.sub.2 O.sub.3, from about 5 to about 30% MgO, from about 20 to about 40% CaO, and from about 2 to about 10% Na.sub.2 O and/or K.sub.2 O. Within the above limits the ratio of the components can vary within the following ranges: SiO.sub.2 /CaO=1.6-2.25, SiO.sub.2 /MgO=2.8-5.7, CaO/MgO=1.5-3.4, SiO.sub.2 +MgO=2.8-5.7, SiO.sub.2 /CaO+MgO=1-1.42.The foregoing mixture is melted between 1,250.degree. and 1,400.degree. C., then it is allowed to stand, depending on the mass and the casting form used, for a period of 1-4 hours. The melt is cooled in the casting forms between 1,250.degree. and 1,050.degree. C. for a period of 0.5 to 1.

Abstract: The invention concerns a process for solubilizing alumina in minerals, rocks or industrial waste products, in which the starting material in finely divided form is mixed with lime in an amount 1 to 3 moles or more of lime (CaO or Ca(OH).sub.2) for each mole of alumina and optionally 1 mole for each mole of any silica present in the starting material, and at the same time or thereafter with water, the resulting mix is maintained under hydrothermal conditions until the alumina has become solubilized by reaction with the lime, and the product is if necessary comminuted to bring it to a form suitable for leaching out of the solubilized alumina.