Title of Invention

" A MOVABLE ROOF SUPPORT CANOPY AS A SAFEGUARD FOR WORKING UNDER FRESH ROOF IN AN ADVANCING" MINE OR TUNNEL"

Abstract

Abstract In the present invention there is provided a movable roof support canopy to work as a safeguard for the workers working/loading coal/blasted muck under freshly exposed roof after a blasting operation in an advancing mine or tunnel, which comprises in combination a set of corrugated mild steel sheets, telescopic metallic tubes and holders. The set of corrugated steel sheets are of dimensions enough to cover the area between three pair of props which being provided along the side of the mine-drivage / tunnel-heading with a plurality of pairs of telescopic tubes fitted between holders installed in props in a single row in which the protrusion in form of elongated tube as guides to fit the telescopic tubes inside. There is a key hole in holder tube that will match with the key hole in the telescopic tubes so that the tubes are firmly hold with the props and enable supporting of the corrugated sheet to act as an overhead canopy. The holder is having a tightening key in the diametrically opposite side of the tubular protrusion to make a firm grip on the prop. The canopy is having spaces for roof bolting and roof inspection. The canopy is also having arrangement for clamping with the telescopic tubes in case there is a chance of sliding of the canopy in steep seams/inclined drivages. The movable roof support canopy of the present invention is simple to manufacture, easy to install and cheaper in cost.

Full Text

The present invention relates to a movable roof support canopy as a safeguard for working under fresh roof in an advancing mine or tunnel. The present invention particularly relates to a corrugated lightweight canopy made of steel or any hard sheet to be erected along with a set of props in a mine tunnel to protect the persons, working under freshly exposed roof, from local roof fall. The present invention provides a novel metallic canopy useful for safeguarding persons working under a freshly exposed in a mine or a tunnel roof. This canopy can be erected along with the conventional roof supports like a set of wooden props, hydro-mechanical props, steel goal-post supports or any other prop like structures installed properly between roof and floor. The novel canopy of the present invention will be capable of holding itself straight horizontally and sliding over previously fitted horizontal telescopic bars between pairs of vertical props erected on both sides of the mine tunnel and thereby ensures a better safety for the mine workers. In Indian mines about 37% of fatal accidents are taking place due to roof fall. This accident rate is almost same during last 100 years. Many efforts are made for supporting the roof for example with props, roof bolts, w-strap, hydraulic props and power supports. But still there are no supports, which can cover the major portion of freshly exposed roof, to prevent fall of small lump/layers over the miners/workers working in the immediate front face of a Bord and Pillar mining panel or in a tunnel heading. It is well known that various kinds of canopies are used to protect mine workers near working faces especially in longwall panels. But in bord and pillar mining panels no such canopies are used for overhead protection near the immediate front face. Therefore still there is a gap between supporting the freshly exposed roof and providing an overhead blanket protection under the new roof. The workers are still exposed to the unsupported roof created just after blasting. This system of present invention of installing a canopy over the vertical props, erected on both sides of the mine tunnel serves the purpose of providing a blanket cover to the mine workers near the working face in an underground drivage. Extensive efforts have been devoted to the development of various supporting devices of canopy type for mine roofs and tunnels. To highlight the wide mining and tunneling usage and continual efforts, which have been made by other inventors to improve the performance of supporting and safety, a few patent references are provided below for illustration. Reference may be made to European patent no. GB2359315, titled: 'Machine having a protective shield for operator'. This invention relates to the field of "canopy" AND "mine" which comprises of a machine (eg. for use in underground mining) has an operator station with at least one exposed side. A canopy that is supported by a frame, extends over the operator station. The main disadvantage of this canopy is that it has to be attached with a moving machine and this mechanism cannot be used with conventional mining like blasting and manual loading. Reference may be made to patent no. RU2169267, titled: 'Roofing of powered support unit'. This invention relates to the field of "canopy" AND "mine" which comprises of a roofing which has capping with supporting wedges, canopy hinged with capping, hydraulic cylinder controlling the canopy. Capping has pocket opened from below and accommodating canopy made with face cantilever, and supporting wedges installed parallel to packing longitudinal axis. Hydraulic cylinder controlling the canopy is located square to capping longitudinal axis for engagement of hydraulic cylinder with supporting wedges. Hydraulic cylinder controlling the canopy may be installed on canopy and arranged between supporting wedges rigidly secured in capping and made with stops on opposite sides. The main disadvantage of this system is that it to be used in power support for longwall mining only and cannot be used in conventional mining method of driving roadways in underground.Reference may be made to European patent no GB2260558. The invention relates to a mine roof support having means for monitoring the angles made by the canopy and the base with respect to a datum. The angular information may be gathered in a number of different ways and the information used to control subsequent movements of the support. The main disadvantage of this system is that it is used only with power support and cannot be used in conventional mining method of driving roadways in underground. Reference may be made to European patent no GB1522687 wherein a method of supporting a mine or tunnel driven by shotfiring, a crown segment canopy is pre-assembled from segments of crowns, distance pieces and at least one lagging mat, preferably made from wire mesh. After assemblage, using an erector, the canopy is conveyed into freshly advanced drift and lifted to the position indicated by chain lines so that distance pieces and lagging mats can be connected between the canopy and the previously set assembly in drift. The canopy is then further raised into contact with the roof (the position indicated by solid lines), and additional segments and legs are positioned, adjustment being made so that the cross-section of each individual support adapts to the local cross- section of the drift, the periphery of each support contacting the rock at several points, and no backfilling being necessary. The adjustment for each support is provided by a hydraulic leg acting through a butt cap. Alternatively the length of overlap between segments may be varied or the legs and additional segments may be hinged to the canopy and straightened until the supports make tight contact with the rock. The main disadvantage of this system is that it has a complicated design and requirement of a hydraulic system/leg for adjustment. Reference may be made to European patent no GB1414256 entitled 'Mine Roof Support Beams' wherein a roof beam for an advancing mine roof support is provided with a resilient canopy surmounted by runners adapted to slide along the roof during advance. The canopy may be made of conveyor belting be secured by belts and overlie the goaf shield. Holes are provided in the canopy to accommodate cantilever extensions and each runner has a hook at its leading end to engage the beam. Here the main disadvantage is that the canopy is made up of conveyor belt therefore there will be difficulty in installing and making the support straight. Moreover it will consume more time to extend the canopy than doing other progressive works like loading and supporting. Reference may be made to US patent no 4,573,828 entitled 'Roof support suitable for use in mines' wherein a roof support, suitable for use in mines, includes a floor-engaging structure, extendible and contractible prop means carried by that structure, and a roof-engageable canopy supported by the prop means. The canopy comprises a main portion and an extension portion, each of which includes a plate member the upper face of which is engageable with the roof. Fastening means, which are provided for rigidly connecting the extension portion and the main portion together, include at least one connecting member adapted to lie within the thickness of the plate members. Here the main disadvantage is that the canopy is installed over hydraulic prop and this system can only be used in longwall system of mining and not in conventional method of mining. Reference may be made to patent no US 4605341 entitled 'Mine roof support and attachment means therefore' wherein attachment means are provided for attaching a mine roof support to an abutment, (e.g. a flexible conveyor) the attachment means comprising a ram arrangement in the form of at least two rams operable to effect relative movement between the mine roof support and the abutment. The provision of two or more rams instead of the conventional single ram means that smaller bore rams may be used to make it possible to cover or encase the rams in a protective shield without reducing the vertical space available to a miner underneath the mine roof support. Here the main disadvantage is that the canopy is made up of conveyor belt therefore there will be difficulty in installing and making the support straight. Moreover it will consume more time to extend the canopy than doing other progressive works. Reference may be made to patent no US 5938376 entitled 'Automated temporary roof support, bolter and method1 wherein in an automated temporary roof support and roof bolting machine there are several safety features. The machine has forward operator's stations on each side of the machine. All the controls for operating the machine are in the operator's stations. The machine is pulled forward, a precise distance, by a hydraulic cylinder with a limited stroke. The pulling of the machine is controlled by safety switches requiring both operators to operate the switches in unison. Here the main disadvantage is that the canopy is installed over a roof bolting machine so the loaders/miners loading the coal / minerals before this supporting process may not get the advantage of this support. Reference may also be made to patent no. DE4016929, US5039257, US5073067, SU1603006, SU1587210, GB2182704, GB2143271, US4609308, US4190385, US4416566, US4102140 wherein these are not for use in conventional mining practices. The main disadvantages of these systems are that these have complicated designs and requirements of a hydraulic system/leg for adjustment, which is difficult to maintain. All the above-mentioned inventions are of different kind of canopy used for underground mining purposes. The disadvantages of these inventions are in their complicated designs, involve high cost and mostly are used in longwall panel extraction methods. Another disadvantage of these prior arts are that these require very skilled manpower to erect. Yet another disadvantage of these canopies are that these require hydraulic system for operation, which are generally not available in conventional mines. Hydraulic powered systems are generally difficult and costly to maintain in long run. Hence, it is clear from the hitherto known prior art that there is a definite need to provide an intermediate technology between the state of the art power support canopy and the old conventional system of supporting. In India there are very few longwall panels compared to extensive conventional bord and pillar system of mining therefore the system of the present invention will help in improving safety of the persons working under freshly exposed roof. The main object of the present invention is to provide a movable roof support canopy as a safeguard for working under fresh roof in an advancing mine or tunnel, which obviates the drawbacks of the hitherto known prior art as detailed above. Another object of the present invention is to provide a canopy, which is lightweight, simple and easy to install jn a conventional bord and pillar development system of mining or tunnel roadways. Yet another object of the present invention is to provide a locking device in the canopy, to prevent backward sliding which may be used in an inclined underground drivage. Still another object of the present invention is to provide a canopy which can be easily installed with the conventional supports like timber props, steel props, goal-post supports, hydro-mechanical props or any other vertical prop like structures with circular or rectangular cross-section. Still yet another object of the present invention is to provide a canopy, which can help in maintaining interval of supports in rows as per the stipulated support design provided by the country's statutes.A further object of the present invention is to provide a canopy, which is reinforced by telescopic arms extended from the props so that if any roof disturbance takes place than the first impact load will be transmitted to the props, saving the workers beneath. In the present invention there is provided a movable roof support canopy as a safeguard for working under fresh roof in an advancing mine tunnel, which comprises in combination a set of corrugated mild steel sheets, telescopic metallic tubes and holders. The combination consisting of an set of corrugated steel sheets of dimensions to cover the area between three pair of props which being provided along the side of the mine-drivage / tunnel-heading with a plurality of pairs of telescopic tubes fitted between holders en suited in props in a single row. The protrusion in form of elongated tube in the holder as guides to fit the telescopic tubes inside. A key hole in holder tube will match with the key hole in the telescopic tubes to put a key or a bolt in it so that the tubes are firmly hold with the props and enable supporting of the corrugated sheet to act as an overhead canopy. The holder is having a tightening key in the diametrically opposite side of the tubular protrusion to make a firm grip on the prop. After a blasting cycle, the face of the mine or tunnel heading advances about 1.2m. This space of 1.2m remains unsupported creating a danger zone for the workers till the blasted loosen coal/mineral/rocks is evacuated from the face and supported latter on. In the present invention, before this evacuation process starts the canopy is advanced to cover the unsupported freshly exposed roof area upto the face line. This enables the mine/tunnel workers to load the coal/blasted ore i.e., cleaning up of face with confidence from beneath the canopy. After evacuation, the props from the last rows may be dismantled/withdrawn and re-installed at the front row nearest to the face, to hold up and support the advanced part of the canopy as well as the roof. Accordingly the present invention provides a movable roof support canopy as a safeguard for working under fresh roof in an advancing mine or tunnel, which comprises in combination a set of corrugated mild steel sheets, telescopic metallic tubes and holders, wherein the set of corrugated steel sheets of dimensions to cover the area between atleast three pair of props which being provided along the side of the mine-drivage / tunnel-heading with a plurality of pairs of telescopic tubes fitted between holders en-suited in the props in a single row in which the protrusion in form of elongated tube acts as guides to fit the telescopic tubes inside where a key hole in the said holder tube matches with a corresponding key hole in the said telescopic tubes to enable put a key or a bolt in it so that the tubes are firmly held with the props and enables support to the corrugated sheets to act as an overhead canopy, the said holder being also provided with a tightening key in the diametrically opposite side of the tubular protrusion to enable make a firm grip on the prop, the said canopy roof having inspection holes of different sizes enabling roof bolting, roof inspection and for clamping with the telescopic tubes in case of an inclined drivage. In an embodiment of the present invention, the holder is of diameter or cross section in the range to fit the existing props, which may be circular or rectangular in shape. In another embodiment of the present invention, the peripheral body of the holder consists of an elongated cylindrical protrusion of the order of 30-45cm length and of diameter to hold a telescopic tube, which can be locked with the holder, by a key hole. In still another embodiment of the present invention, the peripheral body of the holder consists of a tightening key, which is provided diametrically opposite to the elongated cylindrical protrusion. In yet another embodiment of the present invention, the telescopic tubes are of the order of 1.2 to 1.6m with keyholes near each end to get locked with the elongated cylindrical protrusion of the holders fitted near the topside of the erected props. In still yet another embodiment of the present invention, the canopy which is made up of strong corrugated steel sheets is slided over the set of two or three telescopic tubes to provide an overhead protection to the worker engaged in loading coal/mineral from the advancing face. In figures 1 to 5 of the drawings accompanying this specification an embodiment of the movable roof support canopy as a safeguard for working under fresh roof in an advancing mine / tunnel, of the present invention is illustrated. In figure 1 to 3 the canopy holder (1) which has an elongated cylindrical hollow protrusion (2) which is having diameter'large enough to just accommodate the telescopic tubes (6,8) of diameter of the order of 8-9cm and of length of order of 1.2 to 1.6m with keyholes (7,9) near each end. These keyholes (7,9) will be able to get locked with the keyhole (5) of the elongated cylindrical protrusion of the holders (2) fitted on the top of the pair of props installed in rows along the side of the mine/tunnel advancing roadway. The tightening key (3) is a screw type device in the holder to hold the prop tightly through a threaded opening (4) placed diametrically opposite to the protrusion (2). The cross section of the holder (1) may be circular or rectangular to fit the cross section of the commonly used props. Figure 4 depicts front view of the method of installation of the canopy (10) over the set of preinstalled props (11) between the freshly exposed roof (12) and floor (13) near the advancing face. Figure 5 depicts top view of the method of installation of the canopy (10) over the set of preinstalled props (11) beneath the freshly exposed roof (12) and near the advancing face (14). Several space in forms of holes (15) of the order of 15-20cm aperture are made in the canopy (10) for installing roof bolts for final supporting of the roof if required or as per statutes. Some space (16) may also be provided for roof inspection. There are some small holes (17) of the order of 2cm diameter for clamping the canopy with the telescopic tubes (6,8) in case there is a chance of sliding of the canopy in steep seams/inclined drivages. The novelty of the movable roof support canopy, resides in its usefulness as a safeguard for working under fresh roof in an advancing mine tunnel, through simple cost-effective constructional features and ease of installation requiring less manpower and having low cost of manufacture. Another novelty of the present invention is that it does not require very skilled labour in installation. Being lightweight it will also take less time to get installed, which may be at par with the rate of advance of the mine roadway/ tunnel Yet another novelty of the present invention is that this movable roof support canopy ensures a system of statutorily advancing of supports before a blasting operation so that the sagging of the strata minimizes. Still another novelty of the present invention is that this movable roof support canopy ensures roof inspection at any time through the inspection holes (15 and 16) provided. Yet still another novelty of the present invention is that this movable roof support canopy provides option for roof bolting under a safe roof i.e below a canopy through the holes (15) made in the canopy (10). Another novelty of the present invention is that this movable roof support canopy provides a guide / template for installing the roof bolts as the holes (15) may be constructed as per the systematic support rule (statute) of the particular mining panel. One further novelty of the present invention is that this movable roof support canopy has an arrangement for clamping with the telescopic tubes in case there is a chance of sliding of the canopy in steep seams/inclined drivages. The novelty of the movable roof support canopy of the present invention for providing a safeguard for working under fresh roof in an advancing mine tunnel, has been realized by the non-obvious inventive step of providing in combination a corrugated steel sheets, telescopic metallic tubes and holders. The corrugated steel sheets is large enough to cover the area between three pair of props which will be preinstalled along the side of the mine-drivage / tunnel. In the hitherto known prior art, there are no such holders with elongated protrusions which act as receptacle to support the telescopic tubes over which the canopy is slided to cover the unsupported roof. Moreover the holder is having a tightening key in the diametrically opposite side of the tubular protrusion to make a firm grip on the prop. The presence of keyholes in the telescopic tubes to match with the keyholes in the holders will prevent any slippage of the tubes between a pair of strongly erected props. These holders will enable to maneuver the canopy in any inclination of the seam. The spaces provided in the canopy will enable to install roof bolts in a particular systematic manner and under a safe roof. Proper inspection can be made by the workers / supervisor through the inspection holes for intactness of the roof. There are arrangements provided for clamping with the telescopic tubes in case there is a chance of sliding of the canopy in steep seams/inclined drivages. The system was installed the following steps: 1. A set of six numbers of props, two number of corrugated steel sheets (4 m X 1.5m dimension), and six numbers of holders and six set of telescopic tubes were brought near a development face. 2. All the six props were erected in three rows at an interval of 1.2m between the rows and maintaining a distance of the order of 3m between two props in a row. 3. Six numbers of holders along with the three set of telescopic tubes were installed. 4. The corrugated steel sheets were slided over the telescopic tubes. 5. In case the seam was inclined the corrugated steel sheets were clamped with the telescopic tubes so that there are no chances of sliding inadvertently. 6. After a drilling and blasting takes place the face advances by an order of 1.2m. Therefore after fume clearance the face was inspected and the roof and sides were dressed properly as per the statute and then the corrugated steel sheets were slided near the face to cover the unsupported roof. Although the corrugated sheet covers the unsupported roof area it does not support the area so there is a possibility of roof fall. As the corrugated sheet canopy is placed just beneath 5-6 inches of the roof the fallen mass will not acquire much momentum so the fallen roof may accumulate over the canopy but the miners will be saved from the direct fall of the rock mass which may be dressed and removed afterwards. Care has to be taken to support the roof as soon as the blasted coal/muck is removed so that any further roof disturbance is averted. The following example is given by way of illustration of the working of the invention in actual practice and therefore should not be construed to limit the scope of the present invention. Example-1 The movable roof canopy of the present invention for providing a safeguard for working under fresh roof in an advancing mine tunnel in accordance with the present specification were manufactured as mentioned in figures 1 to 5 of the drawings. Field trials in various mines in Jharia coalfield were conducted. These studies were made to evaluate the performance of the present invention. The results of the experiments such as installation of this supporting mechanism at different mines were studied and are detailed below. In development section mainly by Bord and Pillar method of mining the roadway were constructed using the devices of the present invention. Replicates of these experiments were done using props of different make, size and shapes. After an initial training to the support workers, experiments were conducted with timber props, goal post supports with I-shaped cross section and with hydro-mechanical props also. After a long use of about six months there was no incident of any injury due to roof fall. The supports (mainly roof bolts) were installed perfectly as per the laid down systematic support rule of the mine panel with the help of the template made in the canopy. The canopies could be advanced with ease and was advanced after every blast done in the face to provide an overhead protection during loading of the coal. The main advantages of a movable roof support canopy to be used as a safeguard for working under fresh roof in an advancing mine / tunnel are : 1. Simple design, which can be easily and reliably manufactured and installed using easy installation techniques. 2. Ensures safety of the miners / loaders to get injury from direct fall of lumpy rock / coal from the roof, which many a times become fatal. 3. Ensures proper installing of roof bolts after blasting and loading of the muck due to template provided in the canopy. 4. Ensures inspection of the roof during loading of the coal/ blasted muck beneath the freshly exposed roof. 5. Ensures minimum chances of sliding back in case of inclined drivage. 6. Ensures high confidence level of the workers working beneath the canopy. We claim: 1. A movable roof support canopy as a safeguard for working under fresh roof in an advancing mine or tunnel, which comprises in combination a set of corrugated mild steel sheets, telescopic metallic tubes and holders, wherein the set of corrugated steel sheets of dimensions to cover the area between atleast three pair of props which being provided along the side of the mine- drivage / tunnel-heading with a plurality of pairs of telescopic tubes fitted between holders en-suited in the props in a single row in which the protrusion in form of elongated tube acts as guides to fit the telescopic tubes inside where a key hole in the said holder tube matches with a corresponding key hole in the said telescopic tubes to enable put a key or a bolt in it so that the tubes are firmly held with the props and enables support to the corrugated sheets to act as an overhead canopy, the said holder being also provided with a tightening key in the diametrically opposite side of the tubular protrusion to enable make a firm grip on the prop, the said canopy roof having inspection holes of different sizes enabling roof bolting, roof inspection and for clamping with the telescopic tubes in case of an inclined drivage. 2. A movable roof support canopy as claimed in claim 1, wherein the holder is of diameter or cross section in the range to fit the existing props, which may be circular or rectangular in shape. 3. A movable roof support canopy as claimed in claim 1-2, wherein the peripheral body of the holder consists of an elongated cylindrical protrusion of the order of 30-45cm length and of diameter to hold a telescopic tube, which can be locked with the holder, by a key hole. 4. A movable roof support canopy as claimed in claim 1-3, wherein the peripheral body of the holder consists of a tightening key, which is provided diametrically opposite to the elongated cylindrical protrusion. 5. A movable roof support canopy as claimed in claim 1-4, wherein the telescopic tubes are of the order of 1.2 to 1.6m with keyholes near each end to get locked with the elongated cylindrical protrusion of the holders fitted near the topside of the erected props. 6. A movable roof support canopy as claimed in claim 1-5, wherein the canopy which is made up of strong corrugated steel sheets is slided over the set of two or three telescopic tubes to provide an overhead protection to the worker engaged in loading coal/mineral from the advancing face. 7. A movable roof support canopy as a safeguard for working under fresh roof in an advancing mine or tunnel, substantially as herein described with reference to the example and figures 1 to 5 of the drawings accompanying this specification.

Documents:

774-del-2006-abstract.pdf

774-del-2006-claims.pdf

774-del-2006-Correspondence-Others-(12-07-2013).pdf

774-del-2006-correspondence-others-1.pdf

774-del-2006-correspondence-others.pdf

774-del-2006-description(complete).pdf

774-del-2006-drawings.pdf

774-del-2006-form-1.pdf

774-del-2006-form-18.pdf

774-del-2006-Form-2-(12-07-2013).pdf

774-del-2006-form-2.pdf

774-del-2006-Form-3-(12-07-2013).pdf

774-del-2006-form-3.pdf

774-del-2006-form-5.pdf