Method of filling aquiferous boreholes with explosives

• US 3,921,497 A
• Filed: 08/27/1973
• Issued: 11/25/1975
• Est. Priority Date: 09/01/1972
• Status: Expired due to Term

• Current Assignee: Maximilian Klunsch, Paul Lingens, Wolfgang Christmann
• Original Assignee: Maximilian Klunsch, Paul Lingens, Wolfgang Christmann
• Inventors: Klunsch, Maximilian, Lingens, Paul, Christmann, Wolfgang
• Primary Examiner(s): Feinberg, Samuel
• Assistant Examiner(s): Tudor, Harold
• Application Number:
  US05/391,722
• Time in Patent Office: 820 Days
• Field of Search: 86/2R,1R,2C 102/22,23,24
• US Class Current: 86/20.15
• CPC Class Codes: F42D 1/10 Feeding explosives in granular or slurry form; Feeding explosives by pneumatic or hydraulic pressure

Abstract

In a method of filling aquiferous boreholes with a powdered ammonium nitrate explosive containing swelling and waterrepellentizing agents which is uncartridged by means of a gaseous propellant from a pressure tank through a conduit, the improvement which comprises feeding said explosive composition to said aquiferous borehole through an orifice positioned toward the bottom of the borehole and thereafter step-wise or continuously withdrawing from the bottom such orifice from such conduit such that the orifice is located no more than 50 cm above the surface of the delivered explosive and below the surface of the water in the borehole.

Claims

1. In a method filling an aquiferous borehole wiTh a powdered and uncartridged explosive containing swelling agents and waterrepellants employing a gaseous propellant issuing from an orifice positioned at the terminal end of a conduit, the improvement which comprises positioning said conduit toward the bottom of said borehole and, during the filling of said borehole with such gaseous repellant and explosives, stepwisely withdrawing said orifice from said borehole while displacing water upwardly in said borehole by said gaseous propellant and maintaining a clearance between said orifice and any powdered and uncartridged explosive deposited in said borehole, the withdrawal of said borehole being such that the orifice is located no more than 50 cm above the surface of any delivered explosive and below the surface of the water in the borehole.

2. A method according to claim 1 wherein said propellant is compressed air.

3. A method according to claim 2 wherein said orifice is maintained no more than 10 cm above the surface of any delivered explosive.

4. A method according to claim 3 wherein the explosive consists of 60 to 98 weight percent ammonium nitrate and 2 to 40 weight percent of a combustible substance, said combustible substance containing up to 10 weight percent, based upon the weight of the explosive, of a swelling agent.

5. A method according to claim 3 wherein said explosive consists of 60-98 weight percent ammonium nitrate and 2-40 weight percent of a combustible substance, said combustible substance containing up to 3 weight percent, based upon the weight of said explosive, of a water-repellentizing agent.

6. A method according to claim 3 wherein the ammonium nitrate content of the explosive is present in both prilled and in ground form, such that the ratio of the prilled to ground form is between 5:

1 and 1;

5.

7. A method according to claim 6 wherein the weight ratio of the prilled form of ammonium nitrate to ground form of ammonium nitrate is 2:

1.

8. A method according to claim 3 wherein the explosive composition is delivered from a pressure tank which feeds said conduit, which pressure tank is filled with an energy-rich explosive at the bottom thereof and an explosive of lesser energy above said energy-rich explosive whereby, as the pressure tank empties from the bottom, the explosive of greater strength is charged into the bottom of said borehole and the explosive of weaker strength is charged into the portion above said bottom.

9. A method according to claim 3 wherein immediately before the commencement of the injection of the explosive, a gaseous propellant is fed through the conduit into the bottom of the borehole whereby to displace a portion of the water contained therein.

10. A method according to claim 9 wherein said propellant is compressed air.

11. A method according to claim 3 wherein the pressure of the compressed air is between 0.5 and 10 kp/cm2 excess pressure.

12. In a method of filling an aquiferous borehole with a powdered and uncartridged explosive containing swelling agents and water-repellants employing a gaseous propellant issuing from an orifice positioned at the terminal end of a conduit, the improvement which comprises positioning said conduit toward the bottom of said borehole and, during the filling of said borehole, continuously withdrawing said orifice from said borehole while issuing from said orifice said gaseous propellant and explosive such that there is maintained a clearance between said orifice and any delivered explosive such that water in said borehole is displaced upwardly by said gaseous propellant, the withdrawal of said orifice being such that the orifice is located no more than 50 cm. above the surface of any delivered explosive and below the surface of the water in the borehole.