DESC:DESCRIPTION:

This is a complete specification for the provisional application 5679/CHE/2014 filed on 11-November-2014.

TECHNICAL FIELD

[001] The present disclosure generally relates to the field of explosives used in mining, more particularly the under-ground coal mining. In particular, the present disclosure relates to a P5 category cap-sensitive, water-gel type permitted explosive composition possessing high air gap sensitivity and its method of manufacture.

BACKGROUND

[002] Bord and Pillar (B&P) method is predominant underground coal mining system contributing about 95% of the total underground coal production in India. Breaking of coal in B&P method in underground mines using explosives is done presently with (i) P1 / P3 category explosives with instantaneous detonators in cut faces & depillaring and (ii) P5 explosives with delay detonators in blasting off-the-solid (BOS) or solid blasting with permitted delay detonators and the later accounts for a major portion of underground production.

[003] In India, this technique of solid blasting of coal in underground mines was started after the development of suitable (i) P5 category explosives and (ii) non-incendive short delay millisecond detonators sometime in 1969. Blasting off-the-solid (BOS) method got wider acceptability due to its various advantages and gradually replaced the cut face blasting method using coal cutting machine (CCM).

[004] The P5 explosives are the weakest of all the permitted explosives and have a limitation of maximum charge weight per shot hole (1000 grams in degree-I mines and 565 grams in coal mines of degree II and III gassiness) leading to low productivity in solid blasting. An average pull (advance) of 0.8 to 1.0 meter with yield of 10 to 16 tonnes per blast, in solid blasting in different geo-mining conditions and coal seam thickness, have never been considered satisfactory for optimum utilization of men and machines at faces. Efforts to mechanise B&P workings by introducing intermediate technology i.e. with side discharge loaders (SDL) and load haul dumpers (LHD) as loading machines, could not achieve expected production targets due to poor availability of blasted coal at the working faces, mainly caused by lower pull and yield of coal per blast. As solid blasting being the widely practised blasting method in development faces in underground coal mines, production from underground coal mines has been far behind expectations.

[005] The researchers and mine managements have realized that India needs a close look to ensure a minimum pull of 1.5 meters per blast in solid blasting (BOS) to ensure enough blasted coal for mechanical handling. Unless this is achieved, low productivity of underground coal mines will continue to plague Indian coal mining industry (Jain, 1996). If an average pull of 1.2 to 1.5 meters is achieved then the yield per blast is expected to go up by ~50% and in turn, coal production also be increased that can have significant bearing on the productivity, efficiency and profitability of the underground coal mines.

[006] Efforts have been reportedly made by researchers and mine-managements to increase the “pull” (or advance) in blasting off the solid in development faces of underground coal mines by (i) use of empty large diameter auger drill holes as free face (ii) use of longer drill rods for longer drill holes, and (iii) optimization of blasting pattern and initiation sequence. The fact that the national average of “pull” per blast in solid blasting has not improved over last 4 decades since its inception, can be taken as an indicator that the efforts made in the past were insufficient.

[007] The “pull” in BOS can be increased by (i) increasing the charge weight per shot hole by developing safer explosives (ii) development of stronger P5 explosives (iii) innovations in the application techniques. However, in order to meet the statutory requirements vis-à-vis incendivity characteristics in highly gassy and coal dust atmospheres, in cannon gallery set-up as per IS: 6609 (Part-II / Section-2), strength of permitted explosives, specifically P5 category, safest among all permitted explosives, is diluted to certain extent by addition of coolants as ingredients. Efforts to design explosives safer than P5 category may warrant the use of coolants to a prohibitive extent thereby making the explosives weaker than the existing P5 explosives and thus may not be able to give satisfactory performance in practical usage conditions. On the other hand, making explosive stronger than the existing P5 explosives may lead to failures in incendivity requirements. Therefore, as far as application of explosives is taken in to account, the any idea or effort for improving pull in BOS can be considered as an “innovation”.

[008] On these lines, CSIR-CIMFR has patented a method for solid blasting in underground coal mines (patent no: 263217, date of grant 14-October-2014) for improving “pull” in development faces of underground coal mines using air-decking of suitable P5 explosive cartridges within the shot hole. It focused on the inherent air gap sensitivity (AGS) of permitted explosives and the aspects such as (i) increase in AGS of an explosive that takes place under the higher confinement conditions such as a shot-hole (ii) such an air-deck can be provided without separate initiation of each deck. Considering these aspects, decking of explosives in longer holes in blasting off-the solid is expected to increase the “pull” and “yield” per blast, provided unfailing detonation of air-decked explosive cartridges is ensured by suitably selecting or developing an explosive and deciding length of the air-decks and the latter should not exceed the maximum distance over which the detonation wave from a primer cartridge (donor) can jump to the receptor cartridges under practical or usage conditions.

[009] In the light of aforementioned discussion, there exists a need for explosive compositions with high air gap sensitivity (AGS) characteristics that are suitable for use in blasting-off-the-solid (BOS) with air decking for improving “pull” in development faces in underground coal mines. The present invention discloses a P5 category cap-sensitive, water-gel type permitted explosive composition possessing high air gap sensitivity and its method of manufacture.

BRIEF SUMMARY

[010] The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

[011] Exemplary embodiments of the present disclosure are directed towards water-gel type explosive compositions of P5 category with high air gap sensitivity (AGS) characteristics. The explosive composition comprises of oxygen-rich substances or oxidizer salts, fuels, fuel-cum-sensitizers, fuel-cum-thickening agents, inert substance-cum-coolants, cross-linking agents, stabilizers, gassing agents, density reducing agents and other agents in an aqueous solution. The specific ingredients used in the composition are as follows: ammonium nitrate and calcium nitrate as oxidizer salts, technical grade urea and sugar as fuels, mono-methyl ammonium nitrate and Aluminium flake grade powder as fuel-cum-sensitizers, guar gum and oxidized guar gum as fuel-cum-thickening agents, sodium chloride as an inert substance-cum-coolant, potassium pyro antimonate and sodium meta antimonate as cross-linkers, di-ammonium phosphate as stabilizer and sodium nitrite as a density modifier.

[012] Another exemplary aspect of the present subject matter is directed towards a method of manufacture of water-gel type explosive compositions resulting in high air gap sensitivity (AGS) characteristics. The process comprises the following steps of: Adding a predetermined quantity of oxidizer salts into a predetermined quantity of a water to get an oxidizers mixture and blending the oxidizers mixture in a blending apparatus to get an oxidizers blend, wherein a predetermined quantity of a first fuel-cum-sensitizer and a predetermined quantity of an inert substance-cum-coolant are optionally added to the oxidizers mixture during blending; Adding a predetermined quantity of a stabilizer and a fuel at a predetermined temperature in a specified order to the oxidizers blend; Adding a predetermined quantity of a fuel-cum-thickening agent to achieve a uniform dispersion; Adding a predetermined quantity of a density modifier to achieve reduction in the density of the thickened mass; Adding a second fuel-cum-sensitizer and a cross-linker to get a cap-sensitive, water-gel explosive mixture; and Filling the cap-sensitive, water-gel explosive mixture into a cartridge.

[013] It is an object of the present invention to disclose water-gel explosive compositions with high air gap sensitivity and are also suitable for use in blasting-off-the-solid (BOS) or solid blasting with air decking for improving “pull” in development faces in underground coal mines.

DETAILED DESCRIPTION

[014] It is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[015] The use of “including”, “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Further, the use of terms “first”, “second”, and “third”, and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another.

[016] According to a non-limiting exemplary embodiment of the present disclosure, water-gel type explosive compositions meeting the requirements of P5 category permitted explosives and having high air gap sensitivity (AGS) characteristics are disclosed that are suitable for use in blasting-off-the-solid (BOS) with air decking for improving “pull” in development faces and de-pillaring in underground coal mines.

[017] In accordance with a non-limiting exemplary embodiment of the present subject matter, a method of manufacture of water-gel type permitted explosive compositions of P5 category with high air gap sensitivity (AGS) characteristics is disclosed.

[018] According to a non-limiting exemplary embodiment of the present disclosure, the P5 category cap-sensitive, water-gel explosive composition comprises of oxygen-rich substances or oxidizer salts, fuels, fuel-cum-sensitizers, fuel-cum-thickening agents, inert substance-cum-coolants, cross-linking agents, stabilizers, gassing agents, density reducing agents and other agents in an aqueous solution.

[019] According to a non-limiting exemplary embodiment of the present disclosure, the composition of the explosive comprises of oxygen rich salts such as Ammonium Nitrate, Sodium Nitrate, Calcium Nitrate, Zinc Nitrate, Potassium Nitrate; Fuels such as Urea, Sugar, Mono-ethylene Glycol; Fuel cum Sensitizers such as Mono-methyl ammonium nitrate, Aluminium flake grade powders, Di-methyl ammonium nitrate, Ethylene diamine di-nitrate; Fuel cum thickening agents like Guar and modified Guar powders, Starches, Cellulose Powders; Inert substances like Sodium chloride, Potassium chloride, Sodium / Potassium carbonates, Potassium bi tartarate; cross-linkers and stabilizers like Potassium pyro antimonate, Sodium meta antimonate, Zinc oxide, Sodium borate, Boric acid, Sodium / Potassium dichromates, Mono / Di Ammonium phosphates; and Density modifiers like particulate bulking agents (Glass Microspheres, Expanded perlites), Sodium nitrite, thio-urea, sodium or potassium or ammonium thio-cyanates and other agents. Any other oxidizer salts, fuels, fuel-cum-sensitizers, fuel-cum-thickening agents, inert substances, coolants, cross linking agents, stabilizers, gassing agents, density reducing agents and other agents known in the art can be used without limiting the scope of the present disclosure.

[020] Inclusion of sensitizers like mono-methyl ammonium nitrate, perchlorate salts and pigment Aluminium in Ammonium Nitrate based water-gel / slurry type explosive compositions can improve air-gap sensitivity but there are certain drawbacks like higher reactivity and high cost as in the case of perchlorate salts. Also, it is found that inclusion of perchlorate salts along with mono-methyl ammonium nitrate in the composition can result in enhanced sensitivity of a composition containing them, making the composition relatively less safe to make, store, transport and use. It has become possible to do away with the perchlorate salt and still achieve enhanced air-gap sensitivity even when packaged in small diameter. Perchlorate salts can also be included in the above said composition and that can lead to formation of a more-sensitive product.

[021] In accordance with a non-limiting exemplary embodiment of the present disclosure, the P5 category cap-sensitive, water-gel explosive composition, mainly comprises of ammonium nitrate and calcium nitrate as oxidizer salts, technical grade urea and sugar as fuels, mono-methyl ammonium nitrate and Aluminium flake grade powder as fuel-cum-sensitizers, guar gum and oxidized guar gum as fuel-cum-thickening agents, sodium chloride as an inert substance-cum-coolant, potassium pyro antimonate and sodium meta antimonate as cross-linkers, di-ammonium phosphate as stabilizer and sodium nitrite as a density modifier. Sodium nitrite present in the composition also acts as a gassing agent. Similarly, potassium pyro antimonate and sodium meta antimonate play a dual role of cross-linking as well as stabilizing the composition.

[022] According to a non-limiting exemplary embodiment of the present disclosure, the tolerance limits of the different ingredients of the cap-sensitive, water-gel explosive composition are as follows: the tolerance limit in percent by weight for ammonium nitrate is 40 ± 2.5, calcium nitrate is 10 ± 1.5, urea is 4 ± 2, sugar is 2.5 ± 1, Mono-methyl ammonium nitrate is 17 ± 2, Aluminium flake grade powder is 3.5 ± 0.5, guar gum is 1 ± 0.5, oxidized guar gum is 0.6 ± 0.2, sodium chloride is 9 ± 1.5 and water is 20 ± 2.

[023] According to a non-limiting exemplary embodiment of the present disclosure, the quantities of the different ingredients in the cap-sensitive, water-gel explosive composition are as follows: ammonium nitrate is about 38% by weight, calcium nitrate is about 9.5% by weight, urea is about 4% by weight, sugar is about 2.5% by weight, Mono-methyl ammonium nitrate is about 15% by weight, Aluminium flake grade powder is about 3.5% by weight, guar gum is about 1% by weight, oxidised guar gum is about 0.6% by weight, sodium chloride is about 8% by weight . The percent by weight of water in the explosive composition is about 18%.

[024] In accordance with a non-limiting exemplary embodiment of the present disclosure, the water-gel type explosive composition is cap/detonator sensitive in cartridges having a diameter of about 32 mm or 37 mm, at temperatures 50 C to 450 C, when initiated with a standard number 6 strength detonator. The explosive composition exhibits high air gap sensitivity characteristics.

[025] According to a non-limiting exemplary embodiment of the present disclosure, the water-gel type explosive composition passes 15 cm Air-Gap Sensitivity (AGS) tests when tested under specified conditions of BIS test methods or under the conditions specified by Directorate General of Mines Safety (DGMS), the statutory authority in India.

[026] According to a non-limiting exemplary embodiment of the present disclosure, the water-gel type explosive composition, passed the statutory requirements of incendivity characteristics in gassy and coal dust atmosphere when evaluated by CSIR-CIMFR-Dhanbad, India (the authorized R&D laboratory in India to carry out such evaluation) under specified conditions in accordance with IS 6609 (Part II / Sec 2) for P5 category of permitted explosives.

[027] According to a non-limiting exemplary embodiment of the present disclosure, a method of manufacture of water-gel type explosive composition is disclosed comprising the steps of preparing a blend with all the oxidizers dissolved in water, adding other ingredients into the said blend in a specified manner, thickening said mass or mixture by a suitable hydro-colloid like guar-gum and allowing the thickened phase to stand for a period of time before mixing the Aluminium powder, stabilizers and cross-linking agents and then packaging into cartridges of specified diameter as described.

[028] In accordance with a non-limiting exemplary embodiment of the present disclosure, a method for manufacture of detonator sensitive water-gel explosive composition packaged in a cartridge is disclosed that comprises the steps of: preparing an oxidizers blend (OB) by dissolving oxidizer salts in the water, optionally adding a total amount or at least a portion of a water soluble sensitizer; optionally adding a total amount or at least a portion of a water soluble inert substance-cum-coolant material; transferring the blend in to a suitable mixer/blender; adding balance portions of water-soluble sensitizer and a water soluble inert substance-cum-coolant material, adding specified stabilizers and fuels in specified quantities, in specified sequence and at specified temperatures into the oxidizers blend; adding specified thickeners in specified quantities so as to achieve uniform dispersion; adding density modifiers for achieving reduction in the density of the resultant thickened mass; adding Aluminium powders, cross-linking agents and stabilizers that render the resulted gel more thicker by way of forming linkages among the thickener molecules so as to result in 3-dimensional net-working, which results in cross-linked gel that remains stable over a period of time; filling the mixture into a cartridge.

[029] According to a non-limiting exemplary embodiment of the present disclosure, the process comprises the following steps of: Adding a predetermined quantity of an oxidizer salts into a predetermined quantity of a water to get an oxidizers mixture and blending the oxidizers mixture in a blending apparatus to get an oxidizers blend, wherein a predetermined quantity of a first fuel-cum-sensitizer and a predetermined quantity of an inert substance-cum-coolant are optionally added to the oxidizers mixture during blending; Adding a predetermined quantity of a stabilizer and a fuel at a predetermined temperature in a specified order to the oxidizers blend; Adding a predetermined quantity of a fuel-cum-thickening agent to achieve a uniform dispersion; Adding a predetermined quantity of a density modifier to achieve reduction in the density of the thickened mass; Adding a second fuel-cum-sensitizer and a cross-linker to get a cap-sensitive, water-gel explosive mixture; and Filling the cap-sensitive, water-gel explosive mixture into a cartridge.

[030] In accordance with a non-limiting exemplary embodiment of the present disclosure, the oxidizer salts are a mixture of an ammonium nitrate and a calcium nitrate, the first fuel-cum-sensitizer is a Mono-methyl ammonium nitrate, the inert substance-cum-coolant is a sodium chloride, the stabilizer is a di-ammonium phosphate, the fuel is a mixture of an urea and a sugar, the fuel-cum-thickening agent is a mixture of a guar gum and an oxidised guar gum, the density modifier is a sodium nitrite, the second fuel-cum-sensitizer is an Aluminium flake grade powder and the cross-linker is at least one of a potassium pyro antimonate and a sodium meta antimonate. In a particular embodiment, the ammonium nitrate is about 38% by weight, the calcium nitrate is about 9.5% by weight, the urea is about 4% by weight, the sugar is about 2.5% by weight, the Mono-methyl ammonium nitrate is about 15% by weight, the Aluminium flake grade powder is about 3.5% by weight, the guar gum is about 1% by weight, the oxidised guar gum is about 0.6% by weight, the sodium chloride is about 8% by weight and the water is about 18% by weight.

[031] The explosive composition manufactured with the above disclosed method of manufacture met with (i) satisfactory cap-sensitivity (ii) statutory requirements of incendivity characteristics in gassy and coal dust atmosphere when evaluated by CSIR-CIMFR-Dhanbad, India (the authorised R&D laboratory in India to carry out such evaluation) under specified conditions in accordance with IS 6609 (Part II / Sec 2) for P5 category of permitted explosives (iii) 15 cm AGS (air gap sensitivity) testing, in 32-mm diameter cartridges, under conditions as per CSIR-CIMFR work instruction No. CMRI/DQM/EEL/WI-07 in the light of the DGMS recommendation of the work shop on “testing of permitted explosives” held in 1994 and minutes of meeting held at DGMS, Dhanbad on 27-11-2003 (iv) Continuity of detonation (COD) testing as per IS 6609 (Part II/Sec 2) (v) the specified requirements in “Assessment of post detonation fumes” determined by CSIR-CIMFR -Dhanbad, India as per the standard laboratory methodology (vi) specified requirements in “Assessment of Deflagration behaviour” determined by CSIR-CIMFR-Dhanbad, India as per the recommendations of the work shop on “testing of permitted explosives” held in 1994 (vii) Assessment of velocity of detonation (VOD) determined by CSIR-CIMFR-Dhanbad, India as per the IS: 6609 (Part II / Sec 1) by D’Autriche method (viii) Assessment of periodic Air Gap Sensitivity (AGS) determined by CSIR-CIMFR-Dhanbad, India as per the parameters said in (iii) above.

[032] The explosive composition disclosed in the present invention, when assessed by CSIR-CIMFR-Dhanbad for continuity of detonation (COD) in 32 mm diameter cartridges, wherein the cartridges were wrapped in paper and fired in open and unconfined conditions, was found to pass all the trials.

[033] The explosive composition disclosed in the present invention, when assessed by CSIR-CIMFR-Dhanbad for continuity of detonation (COD) in PVC spacers with air-decking, passed the configuration of 1P+16cm+1R+16cm+1R+16cm+1R+16cm+1R, wherein P is primer cartridge and R is receptor cartridge.

[034] The explosive composition passed the AGS test in a 32-mm diameter cartridge for an air gap of 16 cm. In periodic testing, after the first month of storage, the explosive composition passed the AGS test with an air gap of 16 cm. After six months of storage, the explosive composition passed the AGS test with an air gap of 15 cm but not 16 cm.

[035] The explosive composition manufactured with the above disclosed method of manufacture, when assessed by CSIR-CIMFR-Dhanbad for AGS in a PVC pipe of 4 mm thick, 40mm ID, passed the configuration of 1P +20 cm+2R i.e. 1 primer cartridge then 20 cm air-gap and then 2 receptor charges exhibiting VOD values from 3877 to 4056 m/s.

[036] In accordance with a non-limiting exemplary embodiment of the present disclosure, a pattern of shot holes drilled parallel or slightly inclined / angular was used while carrying out blasting during trials. With parallel hole pattern, the shot holes were charged with the explosive and the relief holes which provide free face for the blast to progress were left empty.

[037] Although the present disclosure has been described in terms of certain preferred embodiments and illustrations thereof, other embodiments and modifications to preferred embodiments may be possible that are within the principles and spirit of the invention. The above descriptions and figures are therefore to be regarded as illustrative and not restrictive.

[038] Thus the scope of the present disclosure is defined by the appended claims and includes both combinations and sub combinations of the various features described herein above as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description. ,CLAIMS:1. A P5 category cap-sensitive, water-gel explosive composition comprising an oxidizer salt, a fuel, a fuel-cum-sensitizer, a fuel-cum-thickening agent, an inert substance-cum-coolant, a cross-linker, a stabilizer, a gassing agent, a density modifier and optionally, other agents in a water solution, wherein the oxidizer salt is a mixture of an ammonium nitrate and a calcium nitrate, wherein the fuel is a mixture of an urea and a sugar, wherein the fuel-cum-sensitizer is at least one of a Mono-methyl ammonium nitrate and an Aluminium flake grade powder, wherein the fuel-cum-thickening agent is a mixture of a guar gum and an oxidised guar gum, wherein the inert substance-cum-coolant is a sodium chloride, wherein the cross-linker is at least one of a potassium pyro antimonate and a sodium meta antimonate, wherein the stabilizer is a di-ammonium phosphate and wherein the density modifier is a sodium nitrite.

2. The P5 category cap-sensitive, water-gel explosive composition as claimed in claim 1, wherein the ammonium nitrate is about 38% by weight, wherein the calcium nitrate is about 9.5% by weight, wherein the urea is about 4% by weight, wherein the sugar is about 2.5% by weight, wherein the Mono-methyl ammonium nitrate is about 15% by weight, wherein the Aluminium flake grade powder is about 3.5% by weight, wherein the guar gum is about 1% by weight, wherein the oxidised guar gum is about 0.6% by weight, wherein the sodium chloride is about 8% by weight and wherein the water is about 18% by weight.

3. The P5 category cap-sensitive, water-gel explosive composition as claimed in claim 1, has an air gap sensitivity of about 15 cm and has met with the stipulated requirements of incendivity characteristics in gassy and coal dust atmosphere for P5 category of permitted explosives.

4. A process for preparing a P5 category cap-sensitive, water-gel explosive composition comprising:
Adding a predetermined quantity of an oxidizer salts into a predetermined quantity of a water to get an oxidizers mixture and blending the oxidizers mixture in a blending apparatus to get an oxidizers blend, wherein a predetermined quantity of a first fuel-cum-sensitizer and a predetermined quantity of an inert substance-cum-coolant are optionally added to the oxidizers mixture during blending;
Adding a predetermined quantity of a stabilizer and a predetermined quantity of a fuel at a predetermined temperature in a specified order to the oxidizers blend;

Adding a predetermined quantity of a fuel-cum-thickening agent to achieve a uniform dispersion;
Adding a predetermined quantity of a density modifier to achieve reduction in the density of the thickened mass;
Adding a predetermined quantities of a second fuel-cum-sensitizer and a cross-linker to get a cap-sensitive, water-gel explosive mixture; and
Filling a predetermined quantity of a cap-sensitive, water-gel explosive mixture into a cartridge.

5. The process for preparing a P5 category cap-sensitive, water-gel explosive composition as claimed in claim 4, wherein the oxidizer salts are a mixture of an ammonium nitrate and a calcium nitrate, wherein the first fuel-cum-sensitizer is a Mono-methyl ammonium nitrate, wherein the inert substance-cum-coolant is a sodium chloride, wherein the stabilizer is a di-ammonium phosphate, wherein the fuel is a mixture of an urea and a sugar, wherein the fuel-cum-thickening agent is a mixture of a guar gum and an oxidised guar gum, wherein the density modifier is a sodium nitrite, wherein the second fuel-cum-sensitizer is an Aluminium flake grade powder and wherein the cross-linker is at least one of a potassium pyro antimonate and a sodium meta antimonate.

6. The process for preparing a P5 category cap-sensitive, water-gel explosive composition as claimed in claim 5, wherein the ammonium nitrate is about 38% by weight, wherein the calcium nitrate is about 9.5% by weight, wherein the urea is about 4% by weight, wherein the sugar is about 2.5% by weight, wherein the Mono-methyl ammonium nitrate is about 15% by weight, wherein the Aluminium flake grade powder is about 3.5% by weight, wherein the guar gum is about 1% by weight, wherein the oxidised guar gum is about 0.6% by weight, wherein the sodium chloride is about 8% by weight and wherein the water is about 18% by weight.