Title of Invention

"A MOVABLE CANOPY FOR IMMEDIATE FRONT FACE OF MINE OR TUNNEL WORKINGS ALONG WITH ROOF BOLTING SYSTEM OF SUPPORT"

Abstract

In the present invention there is provided a movable overhead 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 heading. The system comprises in combination a set of reinforced metallic sheets, roof bolts, metallic holders, holding ropes, catches and clamps. The set of reinforced metallic sheets are of dimensions enough to cover the area atleast three rows of roof bolts which are provided on the roof of the mine-drivage / tunnel-heading. The roof-bolts are firmly grouted and tightened with bearing plates and nuts. The rope holders are attached in the same threaded portion of the roof-bolts beyond the tightened position of the bearing plate and nut. A steel flexible rope is passed through the rope holders attached in a single row of bolts in which rounded or a hexagonal head is able to rotate/swivel inside the threaded coupling along with the neck of the rope holder. The rope is tightened by a pair of clamps to take up any impact from the roof. The openings provided on the canopies will allow for inspection and roof bolting as per statute or as per requirement. The catches provided in the canopy sheet will restrict inadvertent movement/sliding of canopy in case of any impact or in any inclined drivages. The movable overhead 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 canopy for immediate front face of mine or tunnel workings along with roof bolting system of support. The present invention particularly relates to a system of overhead canopy made up of reinforced steel or any hard sheet that can be mounted along with a set of previously installed roof bolts in a mine tunnel to protect the persons working under freshly exposed roof in an advancing gallery of a mine or a tunnel heading. The present invention provides a novel metallic reinforced 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 roof supports like structures, which are previously installed, grouted and set properly on the roof. The novel canopy of the present invention will be capable of holding itself straight horizontally and sliding over previously fitted metallic rope between pairs of roof bolts or cable bolts erected on roof of the mine tunnel and thereby ensures a better safety for the mine workers in the place where they are most vulnerable to fatal injury. 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 advancing front face of a Bord and Pillar mining panel or in an advancing 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 with the help of previously set roof bolts, erected on roof of the advancing 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 therefore1 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 method' 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 like props and roof bolts. 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 canopy for immediate front face of mine or tunnel workings along with roof bolting system of support, which obviates the drawbacks of the hitherto known prior art as detailed above. Another 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 tunnel, which obviates the drawbacks of the hitherto known prior art as detailed above. Still another object of the present invention is to provide a canopy, which is lightweight, simple and easy to install in a conventional Bord and Pillar development system of mining or in advancing 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 yet another object of the present invention is to provide a canopy, which can be easily installed with the supports like conventional roof bolts or cable bolts previously set on the roof. A further object of the present invention is to provide a canopy, which can help in maintaining interval of roof bolt supports in rows as per the stipulated support design provided by the country's statutes. A still further object of the present invention is to provide a canopy, which is reinforced by a steel cable/rope attached and extended from the roof bolts 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 overhead canopy as a safeguard for working under fresh roof in an advancing mine tunnel, which comprises in combination a set of reinforced mild steel sheets, roof bolts, metallic holders, holding ropes and other accessories. The combination consisting of an set of reinforced metallic sheets of dimensions to cover the area between three rows of roof bolts which being provided on the roof of the mine-drivage / tunnel-heading nearest to the advancing face. Holding ropes of the order of 22mm diameter fitted between rope holders en suited in roof bolts in a single row. Locks in from of clamps are fixed near both the ends of the ropes so that it does not get slackened due to weight of the canopy or due to any external impact on the canopy. The system is having safety catches, which will restrict inadvertent movement/sliding of canopy. 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 roof is dressed and then 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 efface with confidence from beneath the canopy. After evacuation, a new set of roof bolts are installed in the freshly exposed according to the template provided in the canopy. The rope holders along with the ropes from the last rows of roof bolts may be dismantled/withdrawn and re-installed at the front row of the newly installed roof bolts 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 canopy for immediate front face of mine or tunnel workings along with roof bolting system of support, which comprises in combination a set of reinforced metallic sheets, roof bolts, metallic holders, holding ropes, catches and clamps wherein the set of reinforced metallic sheets acting as canopy of dimensions enough to cover the area between atleast three rows of roof bolts which are provided on the roof of the mine-drivage / tunnel-heading, firmly grouted and tightened with bearing plates and nuts fitted between rope holders and the roof in the threaded portion of the roof-bolts wherein a steel flexible rope is passed through the said rope holders attached in a single row of bolts in which rounded or a hexagonal head is able to rotate/swivel inside the threaded coupling along with the neck of the rope holder, the said rope capable of being tightened by a pair of clamps, the said canopy being provided with inspection openings allowing for roof bolting and the said catches provided being capable of restricting inadvertent movement/sliding of canopy in case of any impact or in any inclined drivages. In an embodiment of the present invention, the holder is having a threaded coupling of internal diameter equal to the threaded portion of the roof bolts to enable tightening in the extra threaded portion of the roof-bolt beyond the position of the bearing plate and the tightening nut. In another embodiment of the present invention, the holder consists of a spherical or a hexagonal head, allowing rotation of the rope holder in the threaded coupling. In still another embodiment of the present invention, the length of neck between the head and the rope holder depends on the thickness of the canopy to be slided over the ropes. In yet another embodiment of the present invention, the head is a hexagonal threaded bolt that is capable of being screwed with the rope holder. In still yet another embodiment of the present invention, the ropes that support the canopy, are locked by two clamps fitted near both ends to enable the ropes to take the load of the canopy or any other impact from the roof. In a further embodiment of the present invention, the canopy is made up of strong metallic sheets are slided over the set of two or three holding ropes preinstalled with overhead roof-bolts. In figures 1 to 8 of the drawings accompanying this specification an embodiment of the movable overhead canopy as a safeguard for working under fresh roof in an advancing mine / tunnel, of the present invention is illustrated. In figures 1 to 4 the holder (1), which has a threaded coupling (2) of diameter to fit in the threaded portion of the roof-bolts pre-installed on the roof. A metallic link with the rope holder (5) has been made by a hexagonal bolt or by a spherical shaped head (3) with a neck (4) of length suitable to adjust sliding of the canopy (6). The rope holder (5) is having an opening to fit a rope (17) in the order of 22mm diameter. Figure 3 illustrate the metallic canopy with metallic sheet (6) reinforced by square section hollow or solid bars (8). The canopy is also having catches (10) to prevent inadvertent movement of the canopy. Moreover the canopy is having openings (7) to install roof-bolts (14) on the roof, having diameter large enough to just accommodate the bearing plates (15). There are several inspection holes (9) for roof inspection by the supervisors. Figure 5 and 6 details the mechanism of the safety catches in the catch box (10). A metallic bar or a catch bar (12) is fitted with the help of an axle (11) inside the box. The catch bar (12) is capable of rotation by 90° in one direction inside the catch box through a slot (13). In case the canopy is to be slided against the specified direction for any reason the catch bar (12) is pushed manually inside the slot (13) of the catch box (10) and pushed with the help of a crow bar. Figure 7 depicts front view of the method of installation of the canopies over the set of preinstalled roof-bolts (14) between the freshly exposed roof (23) and floor (25) near the advancing face. The holders are fitted in the remaining threaded portion (20) beyond the bearing plate (15) and the tightening nut (16) of the roof-bolt (14). The holding rope (17) is passed through the rope holder (5) and tightened at the ends by two clamps (18). Then the canopy (6) is slided over two or three rows of roof-bolts installed in between the sides (24) of the mine tunnel. Figure 8 depicts side view of the method of installation of the reinforced canopy (6,8) over the set of preinstalled roof-bolts (14) beneath the freshly exposed roof (23). The figure also shows the previous face line (21) before blasting and new face line (22) after the blasting. It demonstrates how the canopy is providing a overhead safety to the workers who will be engaged in lifting of the blasted rock/coal (19) from the unsupported area just near the advancing new face between (21) and (22). It also shows that the holders and the rope are dismantled from threaded portion (20) of the furthest row of roof-bolts from the new face. The novelty of the movable overhead 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 overhead canopy ensures a system of statutorily advancing of supports like roof-bolting as per template, before a blasting operation so that the sagging of the strata minimizes. Still another novelty of the present invention is that this movable overhead canopy ensures roof inspection at any time through the spaces (9 and 7) provided in the metallic sheet. Yet still another novelty of the present invention is that this movable overhead canopy provides option for roof bolting under a safe roof i.e below a canopy through the holes (7) made in the canopy sheet (6). Another novelty of the present invention is that this movable overhead canopy provides a guide / template for installing the roof bolts, as the holes (7) 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 overhead canopy has a safety catch arrangement for the holding ropes in case there is any chance of sliding in steep seams/inclined drivages. The novelty of the movable overhead 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 set of reinforced metallic sheets, roof bolts, metallic holders, holding ropes, catches and clamps. The presence of square-section metallic bars reinforcements in the set of canopies which will take load of any unwanted impact due to roof-fall from the newly exposed roof, this can save the miners working beneath from direct injury. The canopies are of dimensions enough to cover the area between atleast three rows of roof bolts which are provided on the roof of the mine-drivage / tunnel-heading. Presence of firmly grouted and tightened roof-bolts by bearing plates and nuts make the canopy support stronger to improve its load bearing capacity. The rope holders fitted in the projecting threaded portions of the roof-bolts can take equal load as that of the bolts, without restricting any movement of men and material beneath. A pair of clamps with firm grips tightens the rope with the holders to take care of any inadvertent roof-fall. Presence of openings on the canopies enables roof inspection and roof bolting as per the template of the openings. Presence of safety catches will restrict sliding of canopy in case of any impact or in any inclined drivages. In the hitherto known prior art, there are no such rope-holders, rope with clamps and reinforced canopy with supporting template in combination with pre-installed roof-bolts. The roof-bolts, which act as a receptacle to support the ropes over which the canopy is slided to cover the unsupported roof is an unique novel method and never used earlier. The movable canopy of the present invention for immediate front face of mine or tunnel workings along with roof bolting system of support system was installed as follows: 1. Two number of reinforced steel sheets (4 m X 1.5m dimension), and nine numbers of holders and a set of used mine ropes with clamps were brought near a development face of a coal mine of dimension 4.8m (width) and 3m (height). 2. Roof-bolts were erected in rows at an interval of 1.2m between the rows and maintaining a distance of the order of 1.2m between two roof-bolts in a row. A space of 0.6m space was left along both the sides of the gallery/tunnel side. 3. Nine numbers of holders along with the three ropes were installed in a set of nine preinstalled roof bolts. 4. The reinforced steel sheets were slided over the locked ropes and tightened. 5. In case of inclined seam the canopies were automatically secured by the safety catches 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 blasting fume clearance the face was inspected and the roof and sides were dressed properly as per the statute and then the canopy sheets were slided near the face to cover the unsupported roof. Although the canopy sheet covers the unsupported roof area it does not support the area so there is a possibility of roof fall. As the 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 8 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 roof-bolts of different make, size and shapes. After an initial training to the support workers, experiments were conducted with this new method of roof support with an overhead canopy. 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 the movable canopy of the present invention for immediate front face of mine or tunnel workings along with roof bolting system of support are: 1. Acts as a safeguard for working beneath fresh roof in an advancing mine / tunnel. 2. Simple design, which can be easily, economically, reliably manufactured and installed using easy installation techniques. 3. Easy maintenance as no hydraulic system is used for its operation. 4. 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. 5. Ensures proper installing of roof bolts after blasting and loading of the muck due to template provided in the canopy. 6. Ensures inspection of the roof during loading of the coal/ blasted muck beneath the freshly exposed roof. 7. Ensures minimum chances of sliding back in case of inclined drivage. 8. Ensures high confidence level of the workers working beneath the canopy. 9. Elimination of props that hinders movement of men and materials near the faces. 10. Utilizes the good portion of the used old ropes which otherwise be left in the mines or sent for scrap. We claim: 1. A movable canopy for immediate front face of mine or tunnel workings along with roof bolting system of support, which comprises a set of reinforced metallic sheets, roof bolts, metallic holders, holding ropes, catches and clamps wherein the said set of reinforced metallic sheets (6) acting as canopy of dimensions enough to cover the area between atleast three rows of roof bolts (14) which are provided on the roof of a minedrivage / tunnel heading, firmly grouted and tightened with bearing plates(15) and nuts (16) fitted between rope holders(5) and the roof in the threaded portion of the roof-bolts (14), wherein a steel flexible rope(17) is passed through the said rope holders attached in a single row of bolts in which rounded or a hexagonal head is able to rotate/swivel inside the threaded coupling(2) along with the neck of the said rope holder, the said rope being tightened by a pair of clamps, the said canopy being provided with inspection openings allowing for roof bolting and the said catches(lO) provided so as to restrict inadvertent movement/sliding of the said canopy in case of any impact or in any inclined drivages. 2. A movable canopy as claimed in claim 1, wherein the holder is having a threaded coupling of internal diameter equal to the threaded portion of the roof bolts to enable tightening in the extra threaded portion of the roof-bolt beyond the position of the bearing plate and the tightening nut. 3. A movable canopy as claimed in claim 1-2, wherein the holder consists of a spherical or a hexagonal head, allowing rotation of the rope holder in the threaded coupling. 4. A movable canopy as claimed in claim 1-3, wherein the length of neck between the head and the rope holder depends on the thickness of the canopy to be slided over the ropes. 5. A movable canopy as claimed in claim 1-4, wherein the head is a hexagonal threaded bolt that is being screwed with the rope holder. -19- 6. A movable canopy as claimed in claim 1-5, wherein the ropes that support the canopy, are locked by two clamps fitted near both ends to enable the ropes to take the load of the canopy or any other impact from the roof. 7. A movable canopy as claimed in claim 1-6, wherein the canopy is made up of strong metallic sheets are slided over the set of two or three holding ropes preinstalled with overhead roof-bolts. Dated the...l7"'. day of MARCH, 2006 (Chetan Kumar) ' Scientist ,IPMD Council of Scientific & Industrial Research -20-

Documents:

771-del-2006-Abstract-(05-02-2015).pdf

771-del-2006-abstract.pdf

771-del-2006-Claims-(05-02-2015).pdf

771-del-2006-claims.pdf

771-del-2006-Correspondance Others-(05-02-2015).pdf

771-del-2006-Correspondence-Others-(27-08-2013).pdf

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

771-del-2006-correspondence-others.pdf

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

771-del-2006-drawings.pdf

771-del-2006-Form-1-(05-02-2015).pdf

771-del-2006-form-1.pdf

771-del-2006-form-18.pdf

771-del-2006-Form-2-(05-02-2015).pdf

771-del-2006-form-2.pdf

771-del-2006-Form-3-(27-08-2013).pdf

771-del-2006-form-3.pdf

771-del-2006-Form-5-(05-02-2015).pdf

771-del-2006-form-5.pdf