Claims:We claim:
1. An explosive charging arrangement for open cast mine blasting, the explosive charging arrangement comprising:
two explosive chambers (202, 204) separated vertically via an interface (206), wherein the two chambers (202, 204) comprising explosives with different density as per the requirement of different rock strength.
2. The explosive arrangement as claimed in claim 1, wherein one chamber (202) is occupied by a high-density explosive (208), and the other chamber (204) is occupied with a low-density explosive (210).
3. The explosive arrangement as claimed in claim 2, wherein the high-density explosive (208) is site mixed emulsion (SME) explosive.
4. The explosive arrangement as claimed in claim 2, wherein the high-density explosive (208) is having a density in the range of 1.15 gm/cc to 1.2 gm/cc.
5. The explosive arrangement as claimed in claim 2, wherein the low-density explosive (201) is EPS-epoxy polystyrene mixed with emulsion.
6. The explosive arrangement as claimed in claim 2, wherein the low-density explosive (210) is having a density in the range of 0.8 gm/cc to 1.0 gm/cc.
7. The explosive arrangement as claimed in claim 1, wherein the interface (206) is made up capped hollow polyethylene pipes.

, Description:EXPLOSIVE CHARGING ARRANGEMENT FOR OPEN CAST MINE BLASTING

TECHNICAL FIELD
[0001] The present disclosure, in general, relates to the field of blasting technology and, particularly to an underground mined area opencast mining blasting site. In particular, the present disclosure relates to a unique explosive charging arrangement for open cast mine blasting.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The use of explosive compositions, including but not limited to water gels, slurries, and emulsion-type explosives, in various types of blasting operations, including underground mining, has dramatically increased in recent years because of the economy and excellent explosive characteristics of such compositions. The advent of modern technologies in the manufacture of explosives including emulsions has led to site-mixed slurry explosives. As the name suggests, such site-mixed slurry explosives are manufactured on site in a specially designed pump truck by carrying non-explosive ingredients in separate chambers, mixing them in specific proportions and pumping them in liquid form directly into boreholes. The pumped mixture acquires the characteristics of an explosive within about ten minutes of pumping and solidifies slowly to the shape of the borehole. Unlike bulk emulsions, the site mixed slurry can be pumped in various densities ranging from 0.6 g/cm3 to as high as 1.20 g/cm3 and the energy can be varied to produce different types of chemically balanced explosive products to suit the rock conditions.
[0004] Any of the various known slurry explosives may be used, including water-in-oil emulsions that are well known in the art. U.S. Patent No. 4,931,110, the entirety of which is incorporated by this reference, discloses such an emulsion-type explosive material. Emulsion-type explosives usually contain an emulsifier such as a bis-alkanolamine or bis-polyol derivative of a bis-carboxylated or anhydride derivatized olefinic or vinyl addition polymer. Such emulsifiers impart improved stability and detonation properties to the explosive. Some emulsion-type explosives comprise a water-in-oil emulsion wherein the oil phase is a hydrocarbon fuel component and the dispersed aqueous phase is an aqueous solution of inorganic oxidizing salts. Various other materials, including sensitizing agents and additional fuels, for example, can be employed in a variety of different formulations.
[0005] Also, since pumping emulsion explosives involves the input of dynamic or kinetic energy into the explosive, attendant safety concerns are present. In addition to the potentially high operating pressure required for the pump, various researches indicate that the entire explosive energy generated during blasting is partially used for rock breakage and approximately 80% of the energy is transformed into ground vibration, noise, air pollution, and the like. Among all the adverse effects, ground vibration is a matter of major concern to the planners, designers, and management. Usage of emulsion explosive of fixed density across all mine strata irrespective of rock hardness, compressive strength, mine condition, and other concomitant factors adversely impact blasting cost and fragmentation in varying degrees. This also takes its toll on productivity.
[0006] Therefore, it is desired to have an apparatus or arrangement which can address the issues of the emulsion explosive having fixed density. Indeed, it would be desirable to have an arrangement supporting emulsion explosive with variable density.

OBJECTS OF THE DISCLOSURE
[0007] In view of the foregoing limitations inherent in the state of the art, some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0008] It is a general object of the present disclosure to provide a unique explosive charging arrangement for open cast mine blasting.
[0009] It is an object of the present disclosure to provide an arrangement supporting emulsion explosive with variable density.
[0010] It is another object of the present disclosure to modify prevailing blast geometry for different rock types to achieve the desired results favorably affecting cost, safety, and environmental parameters.
[0011] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY
[0012] This summary is provided to introduce concepts related to a unique explosive charging arrangement for open cast mine blasting. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0013] In an embodiment, the present disclosure relates to a unique explosive charging arrangement for open cast mine blasting. The unique explosive charging arrangement includes two explosive chambers separated vertically via an interface, wherein the two chambers comprising explosives with different density as per the requirement of different rock strength.
[0014] In an aspect, one chamber is occupied by a high-density explosive, and the other chamber is occupied with a low-density explosive.
[0015] In an aspect, the high-density explosive is site mixed emulsion (SME) explosive.
[0016] In an aspect, the high-density explosive is having the density in the range of 1.15 gm/cc to 1.2 gm/cc.
[0017] In an aspect, the low-density explosive is EPS-epoxy polystyrene mixed with emulsion.
[0018] In an aspect, the low-density explosive is having a density in the range of 0.8 gm/cc to 1.0 gm/cc.
[0019] In an aspect, the interface is made up of capped hollow polyethylene pipes.
[0020] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
[0021] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[0022] FIG. 1 illustrates a conventional explosive charging arrangement for open cast mine blasting; and
[0023] FIG. 2 illustrates an explosive charging arrangement for open cast mine blasting in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0024] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0025] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, “consisting” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0027] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0028] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0029] Drilling and Blasting is the first stage in the operation cycle of mining. The efficiency and outcomes of drilling and blasting affect the downstream processes in a significant way. Coal deposits available in banded structure, for which excavation of the waste material is required to access the coal band locked under it. For removal of waste materials, holes are drilled, then these holes are charged with explosives and then remove the waste material after blasting the explosives. Therefore, it is contingent upon every miner to improve the drilling and blasting efficiency for improving the overall productivity of a coal mine.
[0030] As mentioned above, any of the various known slurry explosives may be used, including water-in-oil emulsions that are well known in the art. Generally, in India, site mixed emulsion (SME) explosives having a density of 1.15 gm/cc are used for inducing rock breakage. Various researches indicate that the entire explosive energy generated during blasting is partially used for rock breakage and approximately 80% of the energy is transformed into ground vibration, noise, air pollution etc*. Among all the adverse effects, ground vibration is a matter of major concern to the planners, designers, and management. Usage of explosive of fixed density across all mine strata irrespective of rock hardness, compressive strength, mine condition, and other concomitant factors adversely impact blasting cost and fragmentation in varying degrees. This also takes its toll on productivity.
[0031] In coal mines, geological formations are not naturally uniform. Generally, different hardness quotients are identified in single drilling column 102 (FIG. 1). Using same density site mixed emulsion (SME) 104 across all drilled holes for the blast geometry of a bench resulted in non-uniform and predictable fragmentation. Sometimes, rock chunks would be blocky whereas other instance, the rock chunks would be too loose that productivity would be compromised. So, there is a requirement of different density of explosives in a single column or hole to achieve the desired result.
[0032] To this, the present disclosure relates to a unique explosive charging arrangement for open cast mine blasting (FIG. 2). The unique explosive charging arrangement includes two explosive chambers 202, 204 separated vertically via an interface 206. In an aspect, the interface 206 is made up of capped hollow polyethylene pipes.
[0033] Further, the two chambers 202, 204 comprising explosives with different density as per the requirement of different rock strength.
[0034] In an aspect, one chamber 202 is occupied by a high-density explosive 208, and the other chamber 204 is occupied with a low-density explosive 210.
[0035] In an aspect, the high-density explosive 208 is site mixed emulsion (SME) explosive.
[0036] In an aspect, the high-density explosive 208 is having a density in the range of 1.15 gm/cc to 1.2 gm/cc.
[0037] In an aspect, the low-density explosive 210 is EPS-epoxy polystyrene mixed with emulsion.
[0038] In an aspect, the low-density explosive 210 is having a density in the range of 0.8 gm/cc to 1.0 gm/cc suitable for soft strata with a higher friability index.
[0039] Thus, with the explosive charging arrangement proposed herein, need of blasting in sensitive area, wall control, reduction in back breakage, and low blast hole pressure is successfully addressed. Further, the proposed explosive charging arrangement enables to modify the prevailing blast geometry, as shown in FIG. 1, for different rock types, to achieve the desired results favorably affecting cost, safety, and environmental parameters.
[0040] Thus, with the present disclosure of the subject matter, within the same hole, the low-density explosive is used for strata column that is soft whereas high explosives density is put in the drilled column corresponding to the hard rock formation. Proper interfacing is done. This result in controlling the propagation of vibration, controlling back break and air overpressure, and achieving desired fragmentation without having to pay for high density and costlier explosives, the idea has proved feasible and is resulting in cost saving.
[0041] Furthermore, those skilled in the art can appreciate that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0042] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0043] While the foregoing describes various embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. The scope of the present disclosure is determined by the claims that follow. The present disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.