US2040581A - Mine blasting and similar operations - Google Patents

Mine blasting and similar operations Download PDF

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Publication number
US2040581A
US2040581A US23105A US2310535A US2040581A US 2040581 A US2040581 A US 2040581A US 23105 A US23105 A US 23105A US 2310535 A US2310535 A US 2310535A US 2040581 A US2040581 A US 2040581A
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US
United States
Prior art keywords
plug
stemming
bore hole
charge
blasting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US23105A
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English (en)
Inventor
Voortmann Walter
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Individual
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Individual
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Filing date
Publication date
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Publication of US2040581A publication Critical patent/US2040581A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42D—BLASTING
    • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
    • F42D1/08—Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42D—BLASTING
    • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42D—BLASTING
    • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
    • F42D1/08—Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor
    • F42D1/18—Plugs for boreholes

Definitions

  • the present invention has for its main object 10 to provide a new method of and means for tamping stemming;- and further objects of the invention are a method of and means for accurately controlling cushion ring; a method and means whereby a saving in the quantity of explosive 15 used is eiected and an improved output of materlal is obtained by reducing the amount of dust formed; the elimination of flame; to render it practically impossible to have a. blown-out shot; to eliminate almost entirely the reek produced 20 by the explosive; to render it impossible for the detonator to be exploded when the stemming is being tamped. l
  • a stemming plug oi incombustible material provided with a pulling member which extends outside the bore hole.
  • the stemming plug is rst pushed up against the priming cartridge of the charge by means of the tamping tool which is inserted in the bore hole, then, while holding the pulling member attached to the plug against the tamping tool, the pulling member, i! a cushion is required, is pulled 35 to withdraw the plug to leave a blasting space between the priming cartridge and the stemming plug.
  • lihe length of this space or air cushion is predetermined according to the nature of the rock or the like to be blasted and is measured o by the distance 4by which the pulling member is withdrawn from the mouth of the borehole.
  • the tamping tool is then removed and a quantity of stemmingv inserted in the bore hole'and is tamped tightly against the plug with 45 the stemming tool while at the same time the v pulling member is held to maintain the plug in its correct position and afterwards pulled to force the stemming round the base of the plug, thereby forming a gas-tight seal across the bore hole.
  • the bore hole is then tamped with stemming in the normal manner. Afterwards the stemming is tested by pulling'hard on the pulling member.
  • the stemming can be made completely rigid and ga'stight at the beginning and without any risk of the cartridge and detonator being crushed or damaged while the stemming is tamped.
  • the advantages of accurately controlled ring are obtained.
  • the plug may be firmly held by means of the pulling member at any definitely required distance from the end priming cartridge.
  • this distance is variable and depends upon the nature of the rock or the like to be blasted. The distance will, for instance, be greater with soft rock than with hard rock.
  • the cartridges of the explosive charge will preferably be arranged directly one behind the other Without intervening spaces so that they reach to the bottom of the bore hole.
  • 'I'he invention also comprises a stemming plug for use in the above method, a preferred construction of which comprises a substantially cylindrical body of incombustible material of somewhat smaller diameter than the internal width of the bore hole in which it is to be used, the said plug having a central b'ore for accommodating a non-inammable pulling cord or the like and having one or more lateral grooves through which pass the ignition wires or fuse of the priming cartridge.
  • FIG. 1 shows a lay-out of the charge in a bore hole according to the method of the invention.
  • Fig. 2 illustrates, on a larger scale, a stemming plug according to the invention adapted to be inserted in the bore hole.
  • Fig. 3 shows a view of the left end of the plug according to Fig. 2, also on a larger scale.
  • Fig; 4 shows, on a larger scale, cords of diEerent lengths in combination with plugs according to the invention.
  • Fig. 5 shows, on a smaller scale, an arrangement of bore holes for carrying out the method according to the invention when blasting in a mine.
  • a borehole is bored into the' rock to be blasted, the closed end of which bore hole accommodates explosive cartridges I.
  • the end cartridge at the left is located in the bottom of the bore hole and the other cartridges are so positioned as to succeed the latter without intervening spaces.
  • the end cartridge at the right is the priming cartridge, from which ignition wires 2 lead to the open end of the bor'e hole.
  • a plug 3 which is made of 4incombustible material, or of salt, and the length of which is about one and a half times its diameter, is introduced into the bore hole from the right in such a manner that a cavity H is left free between the end of abacus;
  • the plug 3 is of substantially cylindrical form. It is provided with an axial bore, through which a cord 4 is passed. I'his cord is provided at the end located in the plug withva knot 4 which lies in a corresponding cavity 5 of the plug, said cavity being curved (for instance, semi-spherical)
  • the cylindrical outer surface of the plug is provided with a groove 6, through which pass the ignition wires 2.
  • the cord consists of incombustible material" and is supplied in various lengths, in order to be able to use it for bore holes of diierent lengths.
  • the end of the cord is coloured.
  • the different useful lengths such as 1.50 m., 1.6i) m., 1.70 m., etc., are distinguished by different colours.
  • the vcord of the topplug is longer than the rest.
  • the colour of this cord is indicated by the interruption of the left-hand end of the cord.
  • the diierent marking of the cord of the centre plug is indicated by a chain-dotted line and the marking of the cord of the lower plug by a dotted line.
  • the ignition flame is propagated with certainty up to the cartridge lying at the end of the bore hole. owing to the compact assemblage of the individual cartridges, the explosion wave of the powder gases returns to the cavity H and then acts in the direction of least resistance. Any expulsion of gases is prevented by the tamping of the stemming.
  • the stemming particularly at the beginning, is also tamped so firmly in the bore hole that ejection of the stemming or the plug is avoided.
  • 'I'he size of the cavity H depends on the nature of the rock. 'Ihe harder the rock, the smaller the size of the cavity.
  • 1 denotes diagrammati- I cally a mine being worked. 8 is a gallery in which a shaking conveyor 9 is arranged. At the right of the gallery 8 is a coal seam to be worked.
  • I claimz- 4 In blasting operations, the method of laying a blasting charge in a bore hole in which an incombustible plug having a diameter slightly less than that of the bore hole and a flexible holding member attached thereto is utilized, which comprises the steps of inserting the blasting charge into the bore hole, inserting said plug into the bore hole, tamping stemming material tightly against said plug while the latter is firmly held by said ilexible holding means against movement toward the charge, and then pulling the said plug outwardly by said holding means in order to insure the compactness of the inner portion of the stemming material.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Drilling And Exploitation, And Mining Machines And Methods (AREA)
  • Portable Nailing Machines And Staplers (AREA)
  • Soil Working Implements (AREA)
US23105A 1934-02-16 1935-05-23 Mine blasting and similar operations Expired - Lifetime US2040581A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE449268X 1934-02-16

Publications (1)

Publication Number Publication Date
US2040581A true US2040581A (en) 1936-05-12

Family

ID=6538242

Family Applications (1)

Application Number Title Priority Date Filing Date
US23105A Expired - Lifetime US2040581A (en) 1934-02-16 1935-05-23 Mine blasting and similar operations

Country Status (5)

Country Link
US (1) US2040581A (xx)
BE (2) BE409119A (xx)
DE (1) DE727397C (xx)
FR (2) FR804012A (xx)
GB (1) GB449268A (xx)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481814A (en) * 1941-01-02 1949-09-13 Philadelphia And Reading Coal Connecting sleeve for dynamite cartridges
US2771841A (en) * 1947-08-15 1956-11-27 Fino Anthony J De Belt line charge
US2995087A (en) * 1959-09-04 1961-08-08 Edney Blasting plug
US3179049A (en) * 1959-08-06 1965-04-20 Richfield Oil Corp Stemming device
CN112033245A (zh) * 2020-09-14 2020-12-04 中国矿业大学(北京) 一种长距离炮孔装药装置及装药方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE744063C (de) * 1938-11-29 1944-01-08 Thea Voortmann Geb Aschhoff Pfropfen zum Besetzen von Bohrloechern fuer Sprengzwecke

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2481814A (en) * 1941-01-02 1949-09-13 Philadelphia And Reading Coal Connecting sleeve for dynamite cartridges
US2771841A (en) * 1947-08-15 1956-11-27 Fino Anthony J De Belt line charge
US3179049A (en) * 1959-08-06 1965-04-20 Richfield Oil Corp Stemming device
US2995087A (en) * 1959-09-04 1961-08-08 Edney Blasting plug
CN112033245A (zh) * 2020-09-14 2020-12-04 中国矿业大学(北京) 一种长距离炮孔装药装置及装药方法
CN112033245B (zh) * 2020-09-14 2021-08-13 中国矿业大学(北京) 一种长距离炮孔装药装置及装药方法

Also Published As

Publication number Publication date
FR804012A (fr) 1936-10-14
DE727397C (de) 1942-11-02
BE414203A (xx)
BE409119A (xx) 1935-06-29
GB449268A (en) 1936-06-24
FR47175E (fr) 1937-02-06

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