Title of Invention

A COMPOSITION FOR THE MANUFACTURE OF FLYASH BASED RIGID ROOF SUPPORTS

Abstract

The composition, of the present invention, for the manufacture of flyash based rigid roof supports suitable for underground mines, consists of flyash, an industrial waste from thermal power plants, polymer resins, fibrous material and density modifiers for the manufacture of rigid props, useful in underground mines such as coal and non-coal mines. The flyash based rigid roof supports manufactured from the composition can be used in underground mines as a roof support in place of conventionally used timber and steel roof supports. The flyash based roof support is water and heat resistant and has no rusting effect in mine environment. The compressive strength, tensile strength and failure load are better than timber and it is suitable as roof support for underground mines.

Full Text

This invention relates to a composition for the manufacture of flyash based rigid roof supports suitable for underground mines and a process for the manufacture of rigid roof supports therefrom. Board and pillar is the predominant method of roof support in underground coal and non-coal mining in India. Roof fall still contributes the major share of total accidents in underground mines in spite of extensive use of roof support. Timber and steel props are widely used as roof supports. The timber props contribute the maximum volume of roof support system in underground mining. Huge consumption of timber support in underground mining leads to deforestation and ecological disturbance in environment. Disposal of flyash generated in large quantities from thermal power plants is a major problem. The dispersion of flyash in environment leads to pollution of the atmosphere and increases health hazards to humans, animals and also causes ecological damage by decreasing the fertility of nearby agriculture land. Thus, constructive use of flyash, a thermal power plant waste material, will help reduce environmental pollution. There is definite requirement to develop new types of roof support systems in general for use in underground mines and in particular using waste material like flyash with polymer and other additives having low density, high compressive and tensile strength and good shelf life. This will help solve the ground control problem and also facilitate flyash disposal. Reference may be made to technical report "Development of a pilot scale commercial facility for fabrication and marketing of light weight coal combination by products based artificial support for mine use"(1996), Chugh et al, Southern Illinois University at Carbonate, USA. The work covers utilization of flyash as support material, which is a non-polymerized material product. The support was prepared with the help of cement, which lias brittleness. The drawbacks lie in properties like tensile strength and compressive strength, which were not as required. Reference may be made to Indian Journal of Engineering & Material Sciences, Vol.8, April 2001, pp.90-99. A. Rahim and M. Reaz H. Khondeker used polypropylene fibers with cement and sand to prepare boats. The product lacked adequate tensile and compressive strength. Reference may be made to ACI Mater, M48, 1991. V. M. Malhotra, G. G. Carette and A. Bilodean used polypropylene fibers with flyash. The product lacked adequate tensile and compressive strength. Reference may be made to scientific study of the strength of timber props used in Indian mines, Research paper no. 31, CMRI-E3/31, January 1967. D. A. Narayana Charyulu, S. Ramchandra and K. V. Sundran studied the crippling load, crippling strength, crushing strength and moisture content in different types of wood and found that in 40mm (approx.) diameter sal wood the crippling load was 19000 kg, crippling strength 102.50 kg/cm2 and crushing strength 226.77 kg/cm2. The main object of the present invention is to provide a composition for the manufacture of flyash based rigid roof supports suitable for underground mines such as coal, non-coal mines, which obviates the above noted drawbacks. Another object of the present invention is to provide a process for the manufacture of rigid roof supports suitable for underground mines such as coal, non-coal mines, which obviates the above noted drawbacks. Yet another object of the present invention is to provide rigid roof supports, which are suitable for use as an alternative to timber supports, thus avoiding deforestation. Still another object of the present invention is to provide rigid roof supports, which are suitable for use as an alternative to steel supports in underground mines, which are generally moist and thus cause rusting. A still yet another object of the present invention is to provide rigid roof supports, which have adequate failure load, compressive strength and tensile strength and are suitable for replacement of presently used timber and steel props. A further object of the present invention is to provide a composition, which primarily consists of flyash, an industrial waste product generated in large quantities from thermal power plants, thus providing constructive means of reducing environmental pollution. The composition, of the present invention, for the manufacture of flyash based rigid roof supports suitable for underground mines, consists of flyash, an industrial waste from thermal power plants, polymer resins, fibrous material and density modifiers for the manufacture of rigid props, useful in underground mines such as coal and non-coal mines. The developed flyash based rigid roof supports can be used in underground mines as a roof support in place of timber, which will prevent deforestation to maintain ecological balance. The flyash based roof support is water and heat resistant and has no rusting effect in mine environment and hence can be used instead of steel supports. The compressive strength, tensile strength and failure load are better than timber and it is best suited as roof support in underground mines. Typically, the compressive and tensile strength of timber such as Sal wood are in the range of 581 to 593 Kg/sq. cm. and 221 to 229 Kg/ sq. cm., respectively. Accordingly, the present invention provides a composition for the manufacture of flyash based rigid roof supports suitable for underground mines, which comprises: Flyash: 68.00to75.00 wt% Unsaturated polyester resin : 15.00 to 21.00 wt % Mixture of methyl ethyl ketone peroxide & cobalt: 7.50 to 10.20 wt % Nylon Fiber: 0.50 to 2.00 wt% Density modifier: 0.3 to 0.50 \vi% In an embodiment of the present invention the flyash may be fine particles generated from thermal power plants and collected from electrostatic precipitators (ESP) of the said thermal power plants. In another embodiment of the present invention the resin may be of commercial grade. In yet another embodiment of the present invention the mixture of methyl ethyl ketone peroxide and cobalt may be in 1:1 ratio. In still another embodiment of the present invention the nylon fiber may be of commercial grade. In still yet another embodiment of the present invention the density modifier may be such as commercial grade perforated thermocol, wood powder or mixture thereof. In a further embodiment of the present invention, the composition may consist of : Flyash 68.00 to 75.00 wt % Unsaturated polyester resin 15.00 to 21.00 wt % Methyl ethyl ketone peroxide 3.75 to 5.10wt% Cobalt 3.75 to 5.10wt% Nylon Fiber 0.50 to 2.00 wt% Density modifier 0.3 to 0.50 wt% It is a feature of the present invention that the composition is not a mere admixture but a synergistic mixture having characteristic properties such as failure load, compressive strength and tensile strength which are different to the mere aggregated properties of the individual ingredients and there is no chemical reaction involved in the said composition. Accordingly, the present invention provides a process for the manufacture of flyash based rigid roof supports from the novel synergistic composition of the present invention as detailed above, which comprises mixing thoroughly by conventional methods: Flyash : 68.00 to 75.00 wt%, Unsaturated polyester resin : 15.00 to 21.00 wt %, Mixture of methyl ethyl ketone peroxide & cobalt: 7.50 to 10.20 wt %, Nylon Fiber: 0.50 to 2.00 wt%, Density modifier : 0.3 to 0.50 wt%, to obtain a homogenous mix, filling grease or wax lined steel moulds with the mix so obtained, followed by curing the said mix filled moulds in a conventional curing chamber maintained at a temperature in the range of 80-100°C for a period of the order of two hours, demoulding to obtain flyash based rigid roof supports. The novel flyash based rigid support of the present invention having characteristic properties of failure load, compressive strength and tensile strength is an useful alternative to the conventionally used timber and steel supports for under ground mines. The flyash based rigid supports of the present invention are water and heat resistant, hence there is no rusting effect and can sustain in fiery underground mines. The compressive strength and tensile strength of flyash based rigid roof support is better than the timber of Sal wood which are in the range of 581- 593 Kg/cm2 and 221-229 Kg/cm2, respectively. The above novel features have been made possible as a result of the non-obvious inventive step of providing a synergistic mixture essentially consisting of flyash, an industrial waste from thermal power plants, resins, cobalt, nylon fibre and density modifier. For the manufacture of flyash based rigid roof supports from the novel synergistic composition of the present invention, the ingredients are mixed thoroughly in a pre-decided ratio in the range(s) as detailed above to obtain a homogenous mix and filled in steel moulds well lined inside with grease or wax. The moulds so cast are cured in a conventional curing chamber maintained at a temperature in the range of 80-100°C for a period of the order of two hours. The following examples are given by way of illustration and should not be construed to limit the scope of the present invention. Example 1 The weight percentages of the ingredients in the composition used are (Table Removed) The above said ingredients of the composition were mixed well to obtain a homogenous mix and filled in different sized steel moulds lined inside with wax. The moulds so cast were cured in a conventional curing chamber maintained at a temperature of 80 °C for a period of two hours. Properties of the flyash based roof supports prepared are given in table - 1 : Table - 1(Table Removed) The inference drawn from the results, as given in table-1 above, is that with the increase of diameter the value of failure load, compressive and tensile strength increases. Example 2 The weight percentages of the ingredients in the composition used are: (Table Removed) The above said ingredients of the composition were mixed well to obtain a homogenous mix and filled in different sized steel moulds lined inside with wax. The moulds so cast were cured in a conventional curing chamber maintained at a temperature of 100 °C for a period of two hours. Properties of the flyash based roof supports prepared are given in table - 2 : Table-2(Table Removed) The inference drawn from the results as given in table-2 above is that with the increase of diameter the value of failure load, compressive and tensile strength increases. The characteristic properties of flyash based roof supports prepared from the composition of the present invention are given below in table-3: Table - 3(Table Removed) The main advantages of the present invention are: 1. The failure load, compressive strength and tensile strength of developed flyash based roof support are as good or better than wood. 2. It can be used in place of wood, thus preventing deforestation. 3. There is no moisture and rusting effect in the flyash based roof support. 3. Flyash, an industrial waste, constructively used to reduce environmental pollution. We Claim: 1. A composition for the manufacture of flyash based rigid roof supports suitable for underground mines, which comprises: Flyash: 68.00to75.00 wt%, Unsaturated polyester resin : 15.00 to 21.00 wt %, Mixture of methyl ethyl ketone peroxide & cobalt: 7.50 to 10.20 wt%, Nylon Fiber: 0.50 to 2.00 wt%, Density modifier: 0.3 to 0.50 wt%. 2. A composition as claimed in claim 1, wherein the flyash is fine particles generated from thermal power plants and collected from electrostatic precipitators (ESP) of the said thermal power plants 3. A composition as claimed in claim 1-2, wherein the resin is of commercial grade. 4. A composition as claimed in claim 1-3, wherein the mixture of methyl ethyl ketone peroxide and cobalt is in the ratio of 1:1. 5. A composition as claimed in claim 1-4 wherein the nylon fiber is of commercial grade. 6. A composition as claimed in claim 1-5, wherein the density modifier is such as commercial grade perforated thermocol, wood powder or mixture thereof. 7. A composition as claimed in claim 1-6, wherein the composition consists of: Flyash 68.00 to 75.00 wt % Unsaturated polyester resin 15.00 to 21.00 wt % Methyl ethyl ketone peroxide 3.75 to 5.10wt% Cobalt 3.75 to 5.10wt% Nylon Fiber 0.50 to 2.00 wt% Density modifier 0.3 to 0.50 wt% 8. A process for the manufacture of flyash based rigid roof supports from the composition as claimed in claim 1- 7, which comprises mixing thoroughly by conventional methods: Flyash : 68.00 to 75.00 wt%, Unsaturated polyester resin : 15.00 to 21.00 wt %, Mixture of methyl ethyl ketone peroxide & cobalt: 7.50 to 10.20wt%, Nylon Fiber: 0.50 to 2.00 wt%, Density modifier: 0.3 to 0.50 wt%, to obtain a homogenous mix, filling grease or wax lined steel moulds with the mix so obtained, followed by curing the said mix filled moulds in a conventional curing chamber maintained at a temperature in the range of 80-100°C for a period of the order of two hours, demoulding to obtain flyash based rigid roof supports. 9. A composition for the manufacture of flyash based rigid roof supports suitable for underground mines, substantially as herein described with reference to the examples. 10. A process for the manufacture of flyash based rigid roof supports suitable for underground mines, substantially as herein described with reference to the examples.

Documents:

789-DEL-2002-Abstract(18-1-2008).pdf

789-DEL-2002-Abstract-(05-03-2008).pdf

789-del-2002-abstract.pdf

789-DEL-2002-Claims(18-1-2008).pdf

789-DEL-2002-Claims-(05-03-2008).pdf

789-del-2002-claims.pdf

789-DEL-2002-Correspondence-Others(18-1-2008).pdf

789-DEL-2002-Correspondence-Others-(05-03-2008).pdf

789-del-2002-correspondence-others.pdf

789-del-2002-correspondence-po.pdf

789-DEL-2002-Description (Complete)(18-1-2008).pdf

789-DEL-2002-Description (Complete)-(05-03-2008).pdf

789-del-2002-description (complete).pdf

789-DEL-2002-Form-1(18-1-2008).pdf

789-DEL-2002-Form-1-(14-03-2008).pdf

789-del-2002-form-1.pdf

789-del-2002-form-18.pdf

789-DEL-2002-Form-2(18-1-2008).pdf

789-DEL-2002-Form-2-(05-03-2008).pdf

789-del-2002-form-2.pdf

789-DEL-2002-Form-3(18-1-2008).pdf

789-del-2002-form-3.pdf