BACKGROUND OF THE INVENTION
In the present systems of ventilating underground mines, one of the problems not adequately solved is the presence of dangerous gas and dust immediately adjacent the working face of the mine. The present ventilating systems do not have the inherent ability of continuously diverting the clean air from the end of the line curtain assemblies to the working face which is continuously advancing as the mining machinery and operation removes the material being mined. It is readily apparent to those knowledgeable in the art of mining operations that with the modern, fast, and continuous mining operations, it has become of paramount importance to provide adequate air circulation at the working face area of the mine to continuously remove dangerous gases and dust to thereby insure proper ventilation for the safety of those working underground.
Presently, to attempt to provide the desired ventilation within the working areas of the mine, line curtains are employed along the length of the mine working to, in effect, provide an inlet conduit for clean air and an outlet conduit for the exhaust of dangerous gases which are typically laden with a high degree of dust particles. Clearly, the gases and dust contamination is injurious to the respiratory system of the miners, as well as the principle cause of explosions within the mines. As the mining operation continuously advances away from the end of the line curtain, the flow of ventilating air at the working face becomes less and less effective. Accordingly, the actual mining operations must be periodically stopped and an additional length or section of line curtain must be erected.
It is an object of the present invention to produce a ventilation control system for use in mining operations which overcomes the aforesaid problems and provides an efficient and economically feasible means for achieving air circulation control immediately adjacent the working face of the mines to effectively remove the dangerous gases and dust content therein as the mining operation continues.
The above objectives of the invention may typically be achieved by a mine ventilation control system for use in a mine working having a roof and a floor in association with line curtain comprising an extended surface web of flexible substantially gas impervious sheet material having a leading, a trailing, an upper, and a lower edge portion; a first support means for supporting the upper edge portion of the sheet material; a second support means supporting the first support means to position the upper and lower edge portions of the sheet material adjacent the roof and the floor of the mine working respectively in adjacent substantially parallel relation with the line curtain; and means providing longitudinal movement of the first support means and the associated sheet material relative to the second support means whereby the leading edge portion of the sheet material may be advanced toward the working face of the mine working and the trailing edge portion of the sheet material advanced toward the end of the line curtain most adjacent the working face.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become readily apparent to those skilled in the art from reading the following detailed description of an embodiment of the invention when considered in the light of the accompanying drawings, in which:
FIG. 1 is a fragmentary top plan view of a mine working provided with a ventilation control system incorporating the features of the invention;
FIG. 2 is an elevational view of the system disclosed and illustrated in FIG. 1;
FIG. 3 is a sectional view taken along line 3--3 of FIG. 2;
FIG. 4 is a fragmentary elevational view of the roller mechanism interconnecting the supporting elements of the invention; and
FIG. 5 is a fragmentary perspective view of the first and second supporting elements of the invention and the associated extended surface web of flexible gas impervious sheet material.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to the drawings wherein like reference numerals designate similar parts throughout, there is illustrated an underground mine working having a floor 10, a roof 12, and a working face 14. A line curtain 16 typically formed of an extended sheet of flexible substantially gas impervious material, is suspended within the mine from a header member 18 which is secured to the roof 12 of the mine and extends longitudinally along the mine toward the working face 14. The upper edge portion of the line curtain 16 is provided with a series of spaced apart grommets 20 through which suitable fastening means are employed to adequately secure the line curtain 16 in place. It will be observed that the lower edge portion of the line curtain 16 is in intimate contact with the mine floor 10, while the upper edge portion is in sealing relationship with the roof 12 of the mine through the header 18 to thereby provide an elongate seal extending along the mine terminating short of the working face 14. Thus, the structure assumes a substantially continuous ventilation control system to effectively remove dangerous gases and dust in the region of the working face 14 of the mine and create an air flow in the direction of the arrow in FIG. 1. It will be understood, that the fresh air is directed along one side of the line curtain, while the undesired gases and dust laden air is caused to travel in an opposite direction along the opposite face of the curtain 16. The line curtain 16 is installed in the mine after the mining operation has advanced a predetermined distance. In order to assure proper ventilation and therefore the safety of the miners, it is necessary to constantly be certain that the leading edge of the line curtain 16 is within approximately 10 feet of the working face 14. It will be appreciated that it is extremely difficult and time consuming to stop the mining operation and mining machinery every so many feet of travel to install additional lengths of line curtain.
To assure an effective continuous ventilation control system to remove the dangerous gases and dust in the region of the working face 14 of the mine, the present invention provides a cooperating longitudinally extending line curtain assembly which comprises a first supporting frame including a pair of spaced apart end brackets 22 and 24. The lower portions of the brackets 22 and 24 are coupled together by a generally horizontally extending rod member 26. The opposite ends of the rod member 26 may be secured to the respective brackets by any of the known manners such as for example by welding, threaded fasteners, or the like. The upper portions of the brackets 22 and 24 are typically provided with apertures to receive opposite ends of a cable 28 which is woven through spaced apart grommets 29 of an extensible line curtain 30. In order to impart a certain additional strength and rigidity to the upper edge portion of the line curtain 30, the material forming a line curtain 30 is folded upon itself to produce an upper mine roof engaging heading 32. It has been found desirable in certain instances to cause the cable 28 to be drawn tightly to prestress the rod 26 and produce a slight bow therein which when mounted in the operative position illustrated in the drawings is caused to return to its normal substantially straight form by the load imposed thereon by the weight of the curtain material 30. The curtain 30, as well as the line curtain 16, may be formed of a large number of plastic sheet film materials whether made of polymerizates, condensation products, or cellulosic derivatives. However, it is considered preferable to use sheets of fire resistant or fire retardant material such as those containing chlorine in their composition, for example, vinyl chloride polymers and copolymers, polyvinylidene chloride, vinyl chloride-vinylidene chloride polymers, and the like, or those containing fire-retardant compounds, such as tricresyl phosphate or chlorinated compounds, because of the greater safety provided by such materials. In many instances, it may be found desirable to also provide an integral reinforcing material, in a woven or non-woven condition, to impart greater strength thereto without adding a considerable weight factor.
After the cable 28 has been threaded through the grommets 29 in the heading 32 of the line curtain 30 and drawn tight, the ends thereof are suitably secured to the upper portion of the brackets 22 and 24 by any of the known manners.
Next, a second supporting assembly is positioned within the mine. The second supporting assembly illustrated in the drawings consists of a pair of spaced apart supporting columns 36. Since each of the columns 36 is of the same structure, only a single one will be explained in detail. The supporting columns 36 include a main supporting tubular member 38 and a cooperating upper tubular member 40 which is adapted to slide therewithin. The total overall length of the supporting columns 36 may be varied by causing the tubular member 40 to slide within the tubular member 38. The desired length may be fixed by aligning one of the holes 42 of the tubular member 40 within a hole in the upper portion of the tubular member 36 so that a pin 44 may be inserted therein to militate against any relative movement therebetween.
The uppermost end of the upper tubular member 40 is provided with a mine roof engaging pad 46 adapted to be placed into snug engagement with the roof 12 of the mine; while the lowermost end of the tubular member 38 is provided with a spike-like extension 48 which is adapted to be inserted into the floor 10 of the mine. Clearly, the pin 44 is removed when the supporting column 36 is to be installed in a mine. When the pin 44 is removed the tubular members 38 and 40 are positioned relative to one another such that the pad 46 snugly contacts the roof 12 of the mine and the spike-like extension 48 penetrates the floor 10 of the mine and then the pin 44 is reinserted.
The aforementioned second supporting assembly is employed to support the first supporting assembly is such fashion that the curtain 30 may be moved longitudinally toward the working face of the mine and provide, in effect, an operable extension of the line curtain 16 while not requiring the stopping or cessation of the mining operations and, at all times, provide adequate ventilation in the region of the working face 14 of the mine. To accomplish these objectives, a tubular sleeve 50 surrounds the tubular member 38 of column 36 and may be vertically positioned thereon and secured at the desired position by a set screw having an operating handle 52. Projecting radially outwardly of the sleeve 50 are a pair of vertically spaced apart shafts 54 and 56 for rotatingly supporting rollers 58 and 60, respectively. The rollers 58 and 60 may be provided with suitable bearing means such as ball bearings to enable them to roll freely under specified load requirements.
Pivotally mounted at the outermost end of the upper shaft 54 is a locking plate 62 having a notch 64 formed in the opposite end adapted to receive the outer end of the lower shaft 56. The locking plate 62 may be locked in the position shown in full lines in FIG. 3, 4 and 5 by an internally threaded nut 66. By loosening the nut 66, the locking plate 62 may be swung upwardly about the shaft 54 to the dotted line position illustrated in FIG. 4 to enable the roller assembly to receive the rod 26 of the first supporting assembly. After the rod 26 is thus inserted into the space between the rollers 58 and 60, the locking plates 62 are swung downwardly and locked in position by tightening the fasteners 66.
The curtain 30 may be rigidized by the addition of spaced vertically extending batten pockets 70 adapted to receive suitably formed batten strips 72. In typical installations, the batten pockets 70 are positioned at approximately four foot centers and commence just below the vertical height of the rod 26 and terminate approximately one foot from the mine floor 10. The typical height of the curtain 30 is slightly more than the distance from the floor 10 to the roof 12 so that the stiffened upper heading 32 will be slightly bent over in the installed operative position to form a sealing relation with the roof 12 of the mine while the lower edge of the curtain 30 would be in contact with the floor 10, again for the purpose of providing a seal therebetween.
When the assembly is in the assembled position illustrated in the drawings, the curtain 30 may be manually advanced toward the working face 14 of the mine as the mining operations progress constantly maintaining the desired interval between the leading edge of the curtain 30 and the working face 14 to, at all times, maintain effective mine ventilation control without having to close down or impair the mining operation.
To militate against any retrograde movement of the first supporting assembly and the associated curtain 30, there is provided an angularly extending spike 74 adapted to be received within a tubular socket 76 secured to the brackets 22 and 24 at a substantially 45 degree inclination. As the rod 26 of the first supporting assembly is moved between the rollers 58 and 60 in the direction of the working face 14 of the mine, the spike 74 inserted in the socket 76 as illustrated in FIGS. 1 and 2 will slide along the roof 12; however, any reverse movement of the first supporting assembly is substantially prevented.
In accordance with the provisions of the patent statutes, I have explained the principle and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that the invention may be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.