US2063761A

US2063761A - Coal mining

Info

Publication number: US2063761A
Application number: US29736A
Authority: US
Inventors: Scholz Carl
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-07-03
Filing date: 1935-07-03
Publication date: 1936-12-08
Anticipated expiration: 1953-12-08

Description

FIP'Yti Patented Dec. 8, 1936 eioeanai titration l Carl Scholz, Charleston, W. Va.

No Drawing. Application Jilly 3.1 935,

Serial No. 29,736

6 Claims. (01. 262-1) My invention relates to a method for preventing the formation of dust in the mining of coal, as well as in the subsequent handling of it by the dealer and user.

Dust in coal mines originates from two sources: first, by the operations of mining, such as shearing and cutting by machines, blasting and handling from the face of the seam to the surface; and second, by the liberation of the fine dust which lies between the faces and beddings of the coal in the seam.

In the latter case, this dust probably originated when the coal measures were subjected to a process of. bending and warping due to the movement of geological measures. This dust is impalpably fine, running between one hundred and two hundred mesh, and while the quantity is very small, the fact that it fills the crevices,

. which in gassy mines contain highly inflamma- Q blegases, makes it far more dangerous than the dust generated by the process of mining, and it may become ignited by blast shots" or other causes when brought in contact with sufficient oxygen.

Dust produced by the process of mining, upon exposure to'the atmosphere gradually diminishes in hydrocarbon and therefore becomes less combustible, whereas the fine dust in the faces retains the full amount of gas and is far more dangerous. Coal dust of sufficient fineness will explode with a mixture of one-eighth of an ounce of dust for each cubic foot of air.

Moreover, when an explosion is well started, the floor dust, even including some of the coarse material such as ZO-mesh size or larger, enters actively into aiding the extension of the flame and violence. Hence coal dustiness is dangerous whether on the floor or on the ribs, roof or timbers and an explosion may be initiated from finely divided dust in any of these places.

Very finely divided coal, however, that is thoroughly wet with suitable. liquids is practically free of the danger of either ignition or propagation in connection with explosions.

One of the objects of my invention, therefore, is to provide a method for treating the coal with a suitable liquid to prevent ignition of the coal dust in the vein.

A further object is to fill the crevices in the coal seams with a liquid, thereby displacing gas lying in the seam, reducing the amount of explosives required, preventing shattering of the coal and thereby greatly increasing the percentage of coarse coal.

A still further object of the invention consists in the introduction of an aqueous solution of a deliquescent salt or crude oil which will prevent dust, not only in the mine but also in the handling and using of the coal after it has left the mine.

With these and other objects in view my invention consists in certain novel features as will be hereinafter'more fully described and partic;

ularly pointed out in the claims.

In carrying out my process, I drill a number of holes in the coal seam and then before shooting the coal; force in a suitable liquid-such as water, crude oil or an aqueous solution of adeliquescent salt, under very high pressure, ranging from about 400 to 800 pounds per square inch, depending upon the physical structure of the coal seam. These holes should preferably be drilled and treated before the coal is undercut, otherwise, since a very applied, the liquid not saturate the coal in the back of the hole to thefaca' h The present practice is to undercut the coal first and drill the blasting holes afterwards but I have discovered that it is preferable to drill the holesfirst, inject the liquid and then undercut, in order to pr vent the mining machine cuttings from gettinginto the'ventilating cur rents. The holes in which the liquid is injected can be used for shooting the coal down and no other or special holes need be drilled. Subject to the above disadvantages, the holes may be drilled after undercutting and still be within the spirit of the invention and additional holes may be drilled over the blasting holes in order to obtain complete saturation.

The necessary number of holes having been drilled, the liquid is forced into the holes under the desired pressure. Any suitable form of apparatus may be used for forcing the liquid in the holes as will be readily apparent to those skilled in the art.

For a suitable liquid, I may use water, or crude oil or a strong aqueous solution of calcium chloride or other deliquescent salt. The advantage of using this kind of a salt solution resides in the fact that after the water of solution has evaporated, crystals of calcium chloride will be deposited on the coal. Subsequently these crystals deliquesce or break down giving up the Water of crystallization and in this way a moist coating is made on the coal. Any of the fine dust that is wetted with the salt solution will be kept wet longer than with water and thus prevented from exploding. The dust highpressure is will percolate through d,

on the coal that is being distributed to the consumer will also be prevented from drying out.

By forcing the liquid directly into the coal seam, the desired results can be attained with a less quantity than if the coal is sprayed with the liquid.

By following my invention, the entire output of the mine can be made dustless before it is brought to the surface and at a minimum cost. It is superior to a process of spraying certain sizes on the tipple or in the dealers yard, where the liquid covers only the surface of the coal because in my process, the dust allaying liquid penetrates all of the coal.

Some of the advantages of my process are:

First-Safety.-The introduction of a liquid, under pressure, into the coal vein drives out the gases existing between the faces and in the crevices of the coal-bed and moistens the very fine, but highly inflammable dust, which is liberated by blasting. It allays the dust created by the undercutting machines, which is a great menace to safety and is injurious to machine operators. Where grain or pellet powder is used, the moisture prevents the ignition of coal which frequently results in serious mine fires. The elimination of cutter bar dust is one of the greatest safety features sought by the coal mining industry.

Second-Economy.-The filling of crevices in the coal seam with liquid renders it more resistant to the explosive, thus requiring lesser quantities, which in turn results in larger percentage of the coarser sizes.

Third-Sales advantages.The use of the liquid in drill holes will thoroughly saturate the vein and a smaller quantity will produce superior results than can be obtained by spraying.

By drilling and treating the working faces with power drills used in connection with the processing equipment, the labor costs will be no greater than where holes are drilled by hand and better results will be obtained from this method, than if left to the individual coal loader. A corresponding reduction in loading rates would be made if drilling and shooting is performed by the mining company. The

processing is performed by one or more small outfits depending upon the tonnage to be treated and the quantity of fluid used can be accurately measured, depending upon the requirements of the trade.

The liquid that is employed may contain pigments, or other coloring material or powdered metallic bronze, such as is used in paints, which will impart a certain sheen to the coal, giving it a distinctive color, which can be used as a. trademark to identify the origin of the coal. The color or metallic luster will not show up in all coals, but in the splint variety, where the faces are filled with fine dust, the color will show up clearly.

I claim:

1. In the mining of coal, the steps comprising drilling holes in the coal seam and then forcing a liquid under high pressure into the seam for the purpose of preparing the coal for shooting, undercutting the coal and then shooting the coal.

2. In the mining of coal, the steps comprising drilling holes in the coal seam and then forcing oil under pressure into the seam for the purpose of preparing the coal for shooting, undercutting the coal and then shooting the coal.

3. In the mining of coal, the steps comprising drilling holes in the coal seam and then forcing a liquid under a pressure of 400 to 800 pounds per square inch into the seam for the purpose of preparing the coal for shooting, undercutting the coal and then shooting the coal.

4. In the mining of coal, the steps comprising drilling holes in the coal seam, forcing oil under high pressure into the holes to allay the dust, undercutting the coal and then shooting the coal.

5. In the mining of coal, the steps comprising drilling holes in the coal seam, forcing oil under high pressure into the holes to allay the dust and using the said holes as blasting holes for shooting the coal.

6. In the mining of coal, the steps which comprise drilling holes in the coal seam, forcing oil under high pressure into the holes to allay the dust prior to shooting the coal.

CARL SCHOLZ.