Title of Invention	A PROCESS FOR PREPARATION OF SYNERGISTIC COMPOSTION SUITABLE FOR FREE FACE BLASTING IN UNDERGROUND COAL MINES.
Abstract	A process for the preparation of synergistic composition by dissolving oxidizing agent in water at a temperature in the range of 65-70°Cand maintaining pH of the solution in the range of 4.40 to 4.80 by adding acetic acid/nitric acid, adding to the solution so obtained fuel selected from sugar, flour and guar gum and cooling agent selected from sodium chloride to obtain a zero oxygen balanced composition in the slurry form, sensitizing the said slurry by using flake grade aluminium powder followed by treatment with cross-linking agents and gassing agents by known methods.

Title of Invention

A PROCESS FOR PREPARATION OF SYNERGISTIC COMPOSTION SUITABLE FOR FREE FACE BLASTING IN UNDERGROUND COAL MINES.

Abstract

A process for the preparation of synergistic composition by dissolving oxidizing agent in water at a temperature in the range of 65-70°Cand maintaining pH of the solution in the range of 4.40 to 4.80 by adding acetic acid/nitric acid, adding to the solution so obtained fuel selected from sugar, flour and guar gum and cooling agent selected from sodium chloride to obtain a zero oxygen balanced composition in the slurry form, sensitizing the said slurry by using flake grade aluminium powder followed by treatment with cross-linking agents and gassing agents by known methods.

Full Text	This invention relates to a proun for priperation of synergistic composition suitable for free face blasting in underground mines and a process for preparing the said composition. The nitroglycerine (NG) based explosives are available in cartridge form in diameter 32 mm and weight 200 gm. These explosives have velocity of detonation (VOD) ranging from 2400 to 2900 m/sec. and strength from 40 to 45 percent blasting gelatin explosive. The density varies from 1.10 to 1.25 gm/cm3. The nitroglycerine base compositions contain (i) Ammonium nitrate = 55.50%, NG= 20.00%, Nitro-cellulose = 0.50%,Woodflour = 2.50% and Sodium Chloride = 21.5%; Ref. Encyclopedia of Explosives and related items PATR 2700 Vol. 3, p C450-455. Its cartridge materials are waxed paper. These are highly sensitive to shock, friction, heat and flame. The fume quality is poor. When misfired, explosives are mixed in blasted muck may cause accident during loading and thereby increased danger during the operation. In India slurry explosives for cut face blasting are available in cartridge form having a diameter from 32 mm, weight 200 gm. and cartridge material is plastic tube with copper clips or blow molded tube. The available explosive are of poor quality and they deteriorates within six months. Their strength varies from 33-37 % of BG. The explosion temperature of the available explosives are in between 2200-2600 °C with longer flame duration and their explosion energy is in between 1300 - 1400 KJ/kg. Due to the higher explosion temperature and longer flame duration there is a chance of ignition of methane-air mixture and low explosion energy also causes the poor rock breakage. Their velocity of detonation varies from 2900 to 3300 m/sec. and density 1.10 to 1.20 gm/cm3. The available explosives have also lower explosion energy, and poor shelf life. The above drawbacks may be overcome by using suitable ingredients in appropriate quantity. Higher percentage of water in the formulation makes composition poor shelf life and affects its explosive parameters. Low percentage of water creates problem which makes explosives hard and grainy due to the crystallization of inorganic oxidizer salts on the contrary a higher percentage of water decreases the sensitivity as well as the strength, Ref. T. Urbanski, Chemistry and Technology of Explosives, P. 546- 547, Vol. 4. Nabiullah, B. M. P. Pingua, Jagdish and T. N. Singh (Patent No. 3071/DEL/98) has patented the explosive composition useful for safe blasting of coal and claimed the composition in the range of (g/100) Ammonium nitrate 40.15 to 41.10, Calcium nitrate 13.50 to 14.00, Aluminium (flake grade) 2.50 to 3.00, Sugar 7.34 to 7.40, Urea 1.80 to 2.36, Thio-urea 0.90 to 1.00, Sodium chloride 14.01 to 14.50 and Water 18.45 to 19.00. The composition was prepared for highly gassy mine in P-5 conditions. B. M. P. Pingua, Nabiullah, Jagdish and B. B. Dhar patented ( Patent No. 2642/DEL/1996) a coal base composition for surface blasting for dry holes. The composition claimed was (g/100) (i) Ammonium nitrate = 92.00, Coal powder = 6.4, Guar gum = 0.8, Sodium nitrite = 0.4 and Potassium dichromate = 0.4. (ii) Ammonium nitrate = 73.6, Sodium nitrate = 15.6, Coal powder = 8.8, Guar gum = 1.5, Sodium nitrite = 0.2 and Potassium dichromate = 0.3. The main objective of the present invention is to provide a synergistic composition suitable for free face blasting in underground coal mines. The shelf life of this synergistic composition is more than six months. The velocity of detonation of explosive composition is in between 3200 - 3400 m/sec. The explosion temperature varies from 1700 -1800 °C with short flame duration. It has the sufficient explosion energy in between 1650 -1700 kJ/kg to break the rock with good fragmentation. The strength of this composition is in between 38-40% of BG. Another object of the present invention is to provide a process for preparing the novel composition. Still another object is to develop an explosive composition which would be permitted_for cut face blasting of coal in degree- II underground mines. Gassy seam of the degree-II mine is a coal seam or part thereof lying within the precinct of a mine not being an open cast working in which the percentage of inflammable gas in the general body of air at any place in the working seam is more than 0.1 or the rate of emission of inflammable gas per ton of coal produced exceeds one cubic meter but does not exceed ten cubic metres. The P3 group ( P3 explosive formulation are used for cut face blasting in degree- II mine ) of explosive for blasting is in 32 mm diameter and cap - sensitive, low velocity of detonation (less than 3400 m/sec.) and non-incendive in methane and coal dust explosive mixture. Yet another object of the present is to develop a synergistic composition for cut face blasting which on detonation produce low flame length, flame speed and shorter flame duration, since these are also responsible for the ignition of methane air mixture and coal dust. The composition of the present invention utilizes ingredients of oxidizing agents such as ammonium nitrate and calcium nitrate, reducing agents such as sugar, flour, guar gum and aluminium powder, cross-linking agents such as potassium pyro-antimonate, potassium dichromate or mixture thereof and sodium nitrite as a gassing agent is used to produce zero oxygen balance to provide a composition suitable as a slurry explosive. Accordingly, the present invention provides a synergistic composition suitable for free face blasting in underground coal mines which comprises: Oxidizing agent(s) such as: (a) Ammonium nitrate 40.60 to 40.80 wt % (b) Calcium nitrate 31.30 to 31.40 wt % Reducing agent(s) such as: (a) Aluminium powder 2.75 to 3.00 wt % (b) Sugar 8.95 to 9.13 wt % (c) Flour 1.47 to 1.50 wt % (d) Guargum 0.99 to 1.00 wt % Cooling agent(s) such as: (a) Water 4.30 to 4.50 wt % (b) Sodium chloride 9.00 to 9.10 wt % Cross-linking agent(s) (a) Potassium pyro-antimonate 0.04 to 0.05 wt % Gassing agent(s) (a) Sodium nitrite 0.04 to 0.05 wt% The oxidizing agent used may be such as ammonium nitrate, calcium nitrate (hydrated) or mixture thereof. The reducing agent used may be such as aluminium powder (flake), sugar, flour, guar gum, or mixture thereof. The cooling agent used may be such as sodium chloride, water or mixture thereof. The cross-linking agent used may be such as potassium pyro-antimonate, potassium antimony tartarate, potassium dichrornate or mixture thereof. The gassing agent used may be such as sodium nitrite, Potassium thiocynate or mixture thereof. The oxidizing and reducing agents used may be of 98% purity. The cross-linking agents used may be of 99 % purity. The gassing agents used may be of 99 % purity. In an embodiment of the present invention, the composition may consist of: Ammonium nitrate 40.60 to 40.80 wt% Calcium nitrate 31.30 to 31.40 wt% Aluminium Powder 2.75 to 3.00 wt % Sugar 8.95 to 9.13 wt% Flour 1.47 to 1.50 wt % Guargum 0.99 to 1.00 wt% Sodium chloride 9.00 to 9.10 wt% Water 4.30 to 4.50 wt % Potassium pyro-antimonate 0.04 to 0.05 wt % Sodium nitrite 0.04 to 0.05 wt% It is a feature of the present invention that the composition is not a mere admixture but a synergistic mixture having properties which are different to the mere aggregation of the properties of the individual ingredients. Accordingly the present invention provides a process for preparing the composition of the present invention, which comprises dissolving oxidizing agents in water at a temperature in the range of 65 -70 °C and maintaining pH of the solution in the range 4.40 to 4.80 by adding acetic acid / nitric acid, adding to the solution so obtained fuel such as sugar, flour, guar gum and cooling agent such as chloride to obtain a zero oxygen balanced composition in the slurry form, sensitizing the said slurry by using flake grade aluminium powder followed by treatment with gassing agent, sodium nitrite which forms air bubbles to get the optimum density in the said slurry and potassium pyro-antimonate is added to cross-linked and gelling the product. During the process with aluminium powder no gaseous products are formed, the product formed is Al2O3 (alumina), which is a solid and the heat of formation of Al2O3is very high (396 kcal/mol) and the explosive becomes sensitive to detonate with No. 6 detonator, Ref; R. Meyer, pp13. The composition prepared is sensitized enough to be initiated with copper detonator (No.6) consisting of lead azide, lead styphante, aluminium (ASA) 0.20 gm and pentaerythritol tetranitrate (PETN) 0.22 gm. The velocity of detonation of the synergistic composition was in the range of 3200 -3400 m/sec. The explosion temperature of the product was in between 1700 -1800 Kelvin and its explosion energy was in between 1650-1700 Kj/kg. The strength of the composition was 38-40% of BG. This synergistic composition is quite safe to impact and friction. It produces short flame duration 8 to 9 ms. The synergistic composition was prepared with the help of double nitrates because these composition are more stable than the single nitrate. The ammonium nitrate was taken in the range of 40.60 to 40.80 and calcium nitrate (hydrated) was taken in the range of 31.30 to 31.40. The percentage of ammonium nitrate and calcium nitrate (hydrated) claimed has no other earlier claimed for cut face blasting. This calcium nitrate (hydrated) contains additional four molecules of in-built water which protects the synergistic composition from crystallization and desensitization. Sugar and flour were claimed into the percentage range of 8.95 to 9.13 and 1.47 to 1.50 respectively. These are easily available fuels and economically viable which help the explosive in burning and finally lead to detonation. Guar gum was added in the range of 0.99-1.00 which works as gelling agent as well as fuel in the synergistic composition. The potassium pyro-antimonate and sodium nitrite were taken into the percentage of 0.04 -0.05 which works as a cross-linking and gassing agents. The sodium nitrite forms gas bubbles in the composition and reduced its density to detonation density i.e.; 1.50 to 1.10 g/cm3. The water was claimed in the range of 4.30 to 4.50. Water and sodium chloride works as a coolant. The water controls the explosion temperature and flame by vaporization of water molecules and sodium chloride form an ionization zone of Cl- and Na+ ions around the explosion zone and reduces the temperature and flame duration . In absence of sodium chloride the flame length of explosives were recorded upto 0.5m to 0.6m with flame duration 25-28 ms, Ref: B. M. P. Pingua, Ph. D. work, (continue) unpublished. The following examples are given by way of illustration and should not be construed to limit the scope of the present invention. Example 1. (Table Removed) The oxidizing agents ammonium nitrate (406g) and calcium nitrate (313g) was dissolved 43g of water with constant stirring and heated upto 70 ± 5 ° C. The pH of the solution was maintained by adding dilute nitric acid at 4.40 to 4.80. At this pH the process of cross- linking and gassing rate is slow and the product is more stable due formation of micron size air bubbles. The required fuels such as sugar (91.3g), flour (14.7g) and guar gum (l0g) were added to oxidizing solution. The product is near to zero oxygen balanced in the slurry form. The composition is sensitized by using flake grade aluminium powder followed by treatment with gassing and cross-linking agents, sodium nitrite (0.5g) and potassium pyro-antimonate (0.5g) respectively. In a single batch lOOOg of explosive was prepared and explosive properties were studied (Example 1). Explosive properties of example 1. (Table Removed) The velocity of detonation of the prepared synergistic composition was 3400 m/sec . with explosion temperature 1800 Kelvin. The flame duration was measured by high speed Vedio Technique (Panasonic, model AG-455) was found 9ms. Due to th low explosion temperature and short flame duration (9ms) it is safe in methane air mixture. The flame duration greater than 10-12 ms is unsafe in methane air mixture, Ref. Encyclopedia of Explosives and related items, Vol.3 p-C455-456. The continuity of detonation was passed upto 1m of length. lOKg of fall hammer was dropped from different heights, 1m, 3m and 5m, the explosive has no impact sensitive, Example 2. (Table Removed) The oxidizing agents ammonium nitrate (408g) and hydrated calcium nitrate ( 314g) were dissolved in 45g of water with constant stirring heated at 70 ± 5 ° C. The pH of the solution is maintained by adding dilute nitric acid/ acetic acid at 4.40 to 4.80. At this pH the cross linked and gassing rates were slow and the product more was stable due to formation of micron size air spaces. The required fuels such as sugar (89.50g), flour (15g) and guar gum (l0g) were added to oxidizing solution. The product is near to zero oxygen balanced in the slurry form. The composition is sensitized by using aluminium powder (Flake grade) followed by treatment with gassing agent, sodium nitrite (0.4g) and cross-linking agents, potassium pyro-antimonate (0.4g). In a single batch l000g of explosive was prepared and explosive properties were studied (explosive properties of example 2). Explosive Properties of example 2 (Table Removed) The velocity of detonation of the prepared synergistic composition was 3200 m/sec with explosion temperature 1700 Kelvin. The flame duration was measured by high speed Vedio Technique (Panasonic, model AG-455) was found 8ms. Due to th low explosion temperature and short flame duration (8ms) it is safe in methane air mixture. The flame duration greater than 10-12 ms is unsafe in methane air mixture, Ref. Encyclopedia of Explosives and related items, Vol.3 p-C455-456. The continuity of detonation was passed upto 1m of length. l0Kg of fall hammer was dropped from different heights of 1m, 3m and 5m, the explosive has no impact sensitive. The characteristic explosive properties of the above composition is given below: (Table Removed) The main advantage of the explosive composition of the present invention are: 1. It is a cap sensitive composition. 2. The shelf life of the explosive is more than six months with good strength in between 38-40%ofBG. 3. The composition would be suitable for free face blasting in underground mines. 4. The explosive properties of the cross-linked and gelled composition were good and shelf life was more than six months. 5. It is economically viable. We Claim 1. A process for the preparing the synergistic/composition suitable from which comprises, dissolving oxidizing agent in water at a temperature in the range of 65-70°C and maintaining pH of the solution in the range of 4.40 to 4.80 by adding acetic acid/nitric acid, adding to the solution so obtained fuel selected from sugar, flour and guar gum and cooling agent selected from sodium chloride to obtain a zero oxygen balanced composition in the slurry form, sensitizing the said slurry by using flake grade aluminium powder followed by treatment with cross-linking agents and gassing agents by known methods. 2. A process for preparation of synergistic composition as claimed in claim 1 wherein the Oxidizing agent(s) selected from a) Ammonium nitrate 40.60 to 40.80 wt% b) calcium nitrate 31. 30 to 31.40wt% Reducing agent(s) selected from a) Aluminium powder 2.75 to 3.00 wt% b) Sugar 8. 95 to 9.13wt% c) Flour 1.47 to 1.50wt% d) Guar gum 0.99 to 1.00wt% Cooling agent(s) selected from e) Water 4.30 to 4.50wt% f) Sodium chloride 9.00 to 9.10wt% Cross-linking agent(s) selected from a) Potassium pyro-antimonate 0.04 to 0.05 wt% Gassing agent(s) selected from a) Sodium nitrite 0.04 to 0.05 wt% 3. A process for preparation of synergistic composition as claimed in claim 1 wherein the oxidizing agent used is ammonium nitrate, calcium nitrate (hydrated) or mixture thereof. 4. A process for preparation of synergistic composition as claimed in claim 1 wherein the reducing agent used is aluminium powder (flake), sugar, guar gum, or mixture thereof. 5. A process for preparation of synergistic composition as claimed in claim 1 wherein the cooling agent used is sodium chloride, water or mixture thereof. 6. A process for preparation of synergistic composition as claimed in claim 1 wherein the cross-linking agent used is potassium pyro-antimonate, potassium antimony tartarate, potassium dichromate or mixture thereof. 7. A process for preparation of synergistic composition as claimed in claim 1 wherein the gassing agent used is sodium nitrite, potassium thiocyanate or mixture thereof. 8. A process for preparing the synergistic composition substantially as herein described with reference to the examples.

Full Text

This invention relates to a proun for priperation of synergistic composition suitable for free face blasting in underground mines and a process for preparing the said composition.
The nitroglycerine (NG) based explosives are available in cartridge form in diameter 32 mm and weight 200 gm. These explosives have velocity of detonation (VOD) ranging from 2400 to 2900 m/sec. and strength from 40 to 45 percent blasting gelatin explosive. The density varies from 1.10 to 1.25 gm/cm3. The nitroglycerine base compositions contain (i) Ammonium nitrate = 55.50%, NG= 20.00%, Nitro-cellulose = 0.50%,Woodflour = 2.50% and Sodium Chloride = 21.5%; Ref. Encyclopedia of Explosives and related items PATR 2700 Vol. 3, p C450-455. Its cartridge materials are waxed paper. These are highly sensitive to shock, friction, heat and flame. The fume quality is poor. When misfired, explosives are mixed in blasted muck may cause accident during loading and thereby increased danger during the operation.
In India slurry explosives for cut face blasting are available in cartridge form having a diameter from 32 mm, weight 200 gm. and cartridge material is plastic tube with copper clips or blow molded tube. The available explosive are of poor quality and they deteriorates within six months. Their strength varies from 33-37 % of BG. The explosion temperature of the available explosives are in between 2200-2600 °C with longer flame duration and their explosion energy is in between 1300 - 1400 KJ/kg. Due to the higher explosion temperature and longer flame duration there is a chance of ignition of methane-air mixture and low explosion energy also causes the poor rock breakage. Their velocity of detonation varies from 2900 to 3300 m/sec. and density 1.10 to 1.20 gm/cm3. The available explosives have also lower explosion energy, and poor shelf life. The above drawbacks may be overcome by using suitable ingredients in appropriate quantity. Higher percentage of water in the formulation makes composition poor shelf life and affects its

explosive parameters. Low percentage of water creates problem which makes explosives hard and grainy due to the crystallization of inorganic oxidizer salts on the contrary a higher percentage of water decreases the sensitivity as well as the strength, Ref. T. Urbanski, Chemistry and Technology of Explosives, P. 546- 547, Vol. 4.
Nabiullah, B. M. P. Pingua, Jagdish and T. N. Singh (Patent No. 3071/DEL/98) has patented the explosive composition useful for safe blasting of coal and claimed the composition in the range of (g/100) Ammonium nitrate 40.15 to 41.10, Calcium nitrate 13.50 to 14.00, Aluminium (flake grade) 2.50 to 3.00, Sugar 7.34 to 7.40, Urea 1.80 to 2.36, Thio-urea 0.90 to 1.00, Sodium chloride 14.01 to 14.50 and Water 18.45 to 19.00. The composition was prepared for highly gassy mine in P-5 conditions.
B. M. P. Pingua, Nabiullah, Jagdish and B. B. Dhar patented ( Patent No. 2642/DEL/1996) a coal base composition for surface blasting for dry holes. The composition claimed was (g/100) (i) Ammonium nitrate = 92.00, Coal powder = 6.4, Guar gum = 0.8, Sodium nitrite = 0.4 and Potassium dichromate = 0.4. (ii) Ammonium nitrate = 73.6, Sodium nitrate = 15.6, Coal powder = 8.8, Guar gum = 1.5, Sodium nitrite = 0.2 and Potassium dichromate = 0.3.
The main objective of the present invention is to provide a synergistic composition suitable for free face blasting in underground coal mines. The shelf life of this synergistic composition is more than six months. The velocity of detonation of explosive composition is in between 3200 - 3400 m/sec. The explosion temperature varies from 1700 -1800 °C with short flame duration. It has the sufficient explosion energy in between 1650 -1700 kJ/kg to break the rock with good fragmentation. The strength of this composition is in between 38-40% of BG.
Another object of the present invention is to provide a process for preparing the novel composition.

Still another object is to develop an explosive composition which would be permitted_for cut face blasting of coal in degree- II underground mines. Gassy seam of the degree-II mine is a coal seam or part thereof lying within the precinct of a mine not being an open cast working in which the percentage of inflammable gas in the general body of air at any place in the working seam is more than 0.1 or the rate of emission of inflammable gas per ton of coal produced exceeds one cubic meter but does not exceed ten cubic metres. The P3 group ( P3 explosive formulation are used for cut face blasting in degree- II mine ) of explosive for blasting is in 32 mm diameter and cap - sensitive, low velocity of detonation (less than 3400 m/sec.) and non-incendive in methane and coal dust explosive mixture.
Yet another object of the present is to develop a synergistic composition for cut face blasting which on detonation produce low flame length, flame speed and shorter flame duration, since these are also responsible for the ignition of methane air mixture and coal dust.
The composition of the present invention utilizes ingredients of oxidizing agents such as ammonium nitrate and calcium nitrate, reducing agents such as sugar, flour, guar gum and aluminium powder, cross-linking agents such as potassium pyro-antimonate, potassium dichromate or mixture thereof and sodium nitrite as a gassing agent is used to produce zero oxygen balance to provide a composition suitable as a slurry explosive.
Accordingly, the present invention provides a synergistic composition suitable for free face
blasting in underground coal mines which comprises:

Oxidizing agent(s) such as:
(a) Ammonium nitrate 40.60 to 40.80 wt %
(b) Calcium nitrate 31.30 to 31.40 wt %
Reducing agent(s) such as:

(a) Aluminium powder 2.75 to 3.00 wt %
(b) Sugar 8.95 to 9.13 wt %
(c) Flour 1.47 to 1.50 wt %
(d) Guargum 0.99 to 1.00 wt %
Cooling agent(s) such as:

(a) Water 4.30 to 4.50 wt %
(b) Sodium chloride 9.00 to 9.10 wt %
Cross-linking agent(s)
(a) Potassium pyro-antimonate 0.04 to 0.05 wt % Gassing agent(s)
(a) Sodium nitrite 0.04 to 0.05 wt%
The oxidizing agent used may be such as ammonium nitrate, calcium nitrate (hydrated) or mixture thereof.
The reducing agent used may be such as aluminium powder (flake), sugar, flour, guar gum, or mixture thereof.
The cooling agent used may be such as sodium chloride, water or mixture thereof. The cross-linking agent used may be such as potassium pyro-antimonate, potassium antimony tartarate, potassium dichrornate or mixture thereof.
The gassing agent used may be such as sodium nitrite, Potassium thiocynate or mixture thereof.

The oxidizing and reducing agents used may be of 98% purity. The cross-linking agents used may be of 99 % purity. The gassing agents used may be of 99 % purity. In an embodiment of the present invention, the composition may consist of:
Ammonium nitrate 40.60 to 40.80 wt%
Calcium nitrate 31.30 to 31.40 wt%
Aluminium Powder 2.75 to 3.00 wt %
Sugar 8.95 to 9.13 wt%
Flour 1.47 to 1.50 wt %
Guargum 0.99 to 1.00 wt%
Sodium chloride 9.00 to 9.10 wt%
Water 4.30 to 4.50 wt %
Potassium pyro-antimonate 0.04 to 0.05 wt %
Sodium nitrite 0.04 to 0.05 wt%
It is a feature of the present invention that the composition is not a mere admixture but a synergistic mixture having properties which are different to the mere aggregation of the properties of the individual ingredients.
Accordingly the present invention provides a process for preparing the composition of the present invention, which comprises dissolving oxidizing agents in water at a temperature in the range of 65 -70 °C and maintaining pH of the solution in the range 4.40 to 4.80 by adding acetic acid / nitric acid, adding to the solution so obtained fuel such as sugar, flour, guar gum and cooling agent such as chloride to obtain a zero oxygen balanced composition in the slurry form, sensitizing the said slurry by using flake grade aluminium powder followed by treatment with gassing agent, sodium nitrite which

forms air bubbles to get the optimum density in the said slurry and potassium pyro-antimonate is added to cross-linked and gelling the product.
During the process with aluminium powder no gaseous products are formed, the product formed is Al2O3 (alumina), which is a solid and the heat of formation of Al2O3is very high (396 kcal/mol) and the explosive becomes sensitive to detonate with No. 6 detonator, Ref; R. Meyer, pp13.
The composition prepared is sensitized enough to be initiated with copper detonator (No.6) consisting of lead azide, lead styphante, aluminium (ASA) 0.20 gm and pentaerythritol tetranitrate (PETN) 0.22 gm.
The velocity of detonation of the synergistic composition was in the range of 3200 -3400 m/sec. The explosion temperature of the product was in between 1700 -1800 Kelvin and its explosion energy was in between 1650-1700 Kj/kg. The strength of the composition was 38-40% of BG. This synergistic composition is quite safe to impact and friction. It produces short flame duration 8 to 9 ms.
The synergistic composition was prepared with the help of double nitrates because these composition are more stable than the single nitrate. The ammonium nitrate was taken in the range of 40.60 to 40.80 and calcium nitrate (hydrated) was taken in the range of 31.30 to 31.40. The percentage of ammonium nitrate and calcium nitrate (hydrated) claimed has no other earlier claimed for cut face blasting. This calcium nitrate (hydrated) contains additional four molecules of in-built water which protects the synergistic composition from crystallization and desensitization. Sugar and flour were claimed into the percentage range of 8.95 to 9.13 and 1.47 to 1.50 respectively. These are easily available fuels and economically viable which help the explosive in burning and finally lead to detonation. Guar gum was added in the range of 0.99-1.00 which works as gelling agent as well as fuel in the synergistic composition. The potassium pyro-antimonate and

sodium nitrite were taken into the percentage of 0.04 -0.05 which works as a cross-linking and gassing agents. The sodium nitrite forms gas bubbles in the composition and reduced its density to detonation density i.e.; 1.50 to 1.10 g/cm3. The water was claimed in the range of 4.30 to 4.50. Water and sodium chloride works as a coolant. The water controls the explosion temperature and flame by vaporization of water molecules and sodium chloride form an ionization zone of Cl- and Na+ ions around the explosion zone and reduces the temperature and flame duration . In absence of sodium chloride the flame length of explosives were recorded upto 0.5m to 0.6m with flame duration 25-28 ms, Ref: B. M. P. Pingua, Ph. D. work, (continue) unpublished.
The following examples are given by way of illustration and should not be construed to limit the scope of the present invention.
Example 1.
(Table Removed)
The oxidizing agents ammonium nitrate (406g) and calcium nitrate (313g) was dissolved 43g of water with constant stirring and heated upto 70 ± 5 ° C. The pH of the solution was maintained by adding dilute nitric acid at 4.40 to 4.80. At this pH the process of cross- linking and gassing rate is slow and the product is more stable due formation of micron size air bubbles. The required fuels such as sugar (91.3g), flour (14.7g) and guar gum (l0g) were added to oxidizing solution.
The product is near to zero oxygen balanced in the slurry form. The composition is sensitized by using flake grade aluminium powder followed by treatment with gassing and cross-linking agents, sodium nitrite (0.5g) and potassium pyro-antimonate (0.5g) respectively. In a single batch lOOOg of explosive was prepared and explosive properties were studied (Example 1).
Explosive properties of example 1.

(Table Removed)
The velocity of detonation of the prepared synergistic composition was 3400 m/sec . with explosion temperature 1800 Kelvin. The flame duration was measured by high speed Vedio Technique (Panasonic, model AG-455) was found 9ms. Due to th low explosion temperature and short flame duration (9ms) it is safe in methane air mixture. The flame duration greater than 10-12 ms is unsafe in methane air mixture, Ref. Encyclopedia of Explosives and related items, Vol.3 p-C455-456. The continuity of detonation was passed upto 1m of length. lOKg of fall hammer was dropped from different heights, 1m, 3m and 5m, the explosive has no impact sensitive,
Example 2.
(Table Removed)
The oxidizing agents ammonium nitrate (408g) and hydrated calcium nitrate ( 314g) were dissolved in 45g of water with constant stirring heated at 70 ± 5 ° C. The pH of the solution is maintained by adding dilute nitric acid/ acetic acid at 4.40 to 4.80. At this
pH the cross linked and gassing rates were slow and the product more was stable due to formation of micron size air spaces. The required fuels such as sugar (89.50g), flour (15g) and guar gum (l0g) were added to oxidizing solution.
The product is near to zero oxygen balanced in the slurry form. The composition is sensitized by using aluminium powder (Flake grade) followed by treatment with gassing agent, sodium nitrite (0.4g) and cross-linking agents, potassium pyro-antimonate (0.4g). In a single batch l000g of explosive was prepared and explosive properties were studied (explosive properties of example 2).
Explosive Properties of example 2

(Table Removed)
The velocity of detonation of the prepared synergistic composition was 3200 m/sec with explosion temperature 1700 Kelvin. The flame duration was measured by high speed Vedio Technique (Panasonic, model AG-455) was found 8ms. Due to th low explosion temperature and short flame duration (8ms) it is safe in methane air mixture. The flame duration greater than 10-12 ms is unsafe in methane air mixture, Ref. Encyclopedia of Explosives and related items, Vol.3 p-C455-456. The continuity of detonation was passed upto 1m of length. l0Kg of fall hammer was dropped from different heights of 1m, 3m and 5m, the explosive has no impact sensitive.
The characteristic explosive properties of the above composition is given below:

(Table Removed)
The main advantage of the explosive composition of the present invention are:
1. It is a cap sensitive composition.
2. The shelf life of the explosive is more than six months with good strength in between
38-40%ofBG.
3. The composition would be suitable for free face blasting in underground mines.
4. The explosive properties of the cross-linked and gelled composition were good and
shelf life was more than six months.
5. It is economically viable.

We Claim
1. A process for the preparing the synergistic/composition suitable from which comprises,
dissolving oxidizing agent in water at a temperature in the range of 65-70°C
and maintaining pH of the solution in the range of 4.40 to 4.80 by adding
acetic acid/nitric acid, adding to the solution so obtained fuel selected from
sugar, flour and guar gum and cooling agent selected from sodium
chloride to obtain a zero oxygen balanced composition in the slurry form,
sensitizing the said slurry by using flake grade aluminium powder followed
by treatment with cross-linking agents and gassing agents by known
methods.
2. A process for preparation of synergistic composition as claimed in claim 1
wherein the
Oxidizing agent(s) selected from
a) Ammonium nitrate 40.60 to 40.80 wt%
b) calcium nitrate 31. 30 to 31.40wt%
Reducing agent(s) selected from

a) Aluminium powder 2.75 to 3.00 wt%
b) Sugar 8. 95 to 9.13wt%
c) Flour 1.47 to 1.50wt%
d) Guar gum 0.99 to 1.00wt%
Cooling agent(s) selected from

e) Water 4.30 to 4.50wt%
f) Sodium chloride 9.00 to 9.10wt%
Cross-linking agent(s) selected from
a) Potassium pyro-antimonate 0.04 to 0.05 wt%
Gassing agent(s) selected from
a) Sodium nitrite 0.04 to 0.05 wt%
3. A process for preparation of synergistic composition as claimed in claim 1
wherein the oxidizing agent used is ammonium nitrate, calcium nitrate
(hydrated) or mixture thereof.
4. A process for preparation of synergistic composition as claimed in claim 1
wherein the reducing agent used is aluminium powder (flake), sugar, guar
gum, or mixture thereof.
5. A process for preparation of synergistic composition as claimed in claim 1
wherein the cooling agent used is sodium chloride, water or mixture thereof.
6. A process for preparation of synergistic composition as claimed in claim 1
wherein the cross-linking agent used is potassium pyro-antimonate,
potassium antimony tartarate, potassium dichromate or mixture thereof.
7. A process for preparation of synergistic composition as claimed in claim 1
wherein the gassing agent used is sodium nitrite, potassium thiocyanate or
mixture thereof.
8. A process for preparing the synergistic composition substantially as herein described with reference to the examples.

Documents:

204-del-2001-abstract.pdf

204-del-2001-claims.pdf

204-del-2001-correspondence-others.pdf

204-del-2001-correspondence-po.pdf

204-del-2001-description (complete).pdf

204-del-2001-form-1.pdf

204-del-2001-form-19.pdf

204-del-2001-form-2.pdf

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Patent Number

231932

Indian Patent Application Number

204/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

13-Mar-2009

Date of Filing

27-Feb-2001

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	BRAJ MOHAN PAT PINGUA	CENTRAL MINING RESEARCH INSTITUTE, BARWA ROAD, DHANBAD-826001, BIHAR, INDIA.
2	NABIULLAH	CENTRAL MINING RESEARCH INSTITUTE, BARWA ROAD, DHANBAD-826001, BIHAR, INDIA.
3	JAGDISH	CENTRAL MINING RESEARCH INSTITUTE, BARWA ROAD, DHANBAD-826001, BIHAR, INDIA.
4	TRIBHUWAN NATH SINGH	CENTRAL MINING RESEARCH INSTITUTE, BARWA ROAD, DHANBAD-826001, BIHAR, INDIA.

PCT International Classification Number

C08B 31/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA