US3735704A

US3735704A - Control blasting

Info

Publication number: US3735704A
Authority: US
Inventors: C Livingston
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-02-25
Filing date: 1970-02-25
Publication date: 1973-05-29
Anticipated expiration: 1990-05-29
Also published as: CA1003692A

Abstract

Disclosed herein is a new concept in blasting which is based on a unique theory that permits total utilization of the energy of a blasting charge. The method of this invention enables one, through a set procedure, to control the direction and distance of placement of huge volumes of earth and/or the degree of breakage of a volume of material adjacent the area effected by the blast. The method requires systematic test blasts to determine parameters for use in established formula so that the desired end of control blasting of huge volumes of earth can be attained. The scope of this invention is unlimited in its application to mining, hydropower development, construction projects, etc.

Description

States Patent [191 nite Livingston [111 3,735,704 [451 May 29,1973

[ CONTROL BLASTING [22] Filed: Feb. 25, 1970 [21] Appl. No.: 14,166

OTHER PUBLICATIONS Alan Bauer et aL, How IOC Puts Crater Research to Work, E & MJ, September, 1965.

L. C. Lang, Mining Itabirite on the Bong Range in Liberia, Reprint, Canadian Mining Journal, November, 1965.

DISTURBANCE SHOCK FRONT L. C. Lang, Pit Slope Control by Controlled Blasting,

Reprint, Canadian Mining Journal, December, 1965. L. C. Lang, Blasting Frozen Iron Ore at Knob Lake Reprint, Canadian Mining Journal, August 1966.

Primary ExaminerVerlin R. Pendegrass AttorneySherman and Shalloway [5 7] ABSTRACT Disclosed herein is a new concept in blasting which is based on a unique theory that permits total utilization of the energy of a blasting charge. The method of this invention enables one, through a set procedure, to control the direction and distance of placement of huge volumes of earth and/or the degree of breakage of a volume of material adjacent the area effected by the blast. The method requires systematic test blasts to determine parameters for use in established formula so that the desired end of control blasting of huge volumes of earth can be attained. The scope of this invention is unlimited in its application to mining, hydropower development, construction projects, etc.

33 Claims, 36 Drawing Figures PATENIE' M29 ms SW 01 (1F 21 E C N A B R U T S D SHOCK FRONT mvmwon CLIFTON W. LIVINGSTON BY f f ATTORNEYS PATENIEIJ M29573 8,735,704

sum 02 [1F 21 MAXIMUM PRESSURE ACCOMPANYING MASSIVE GROUNDMOTION PEAK PRESSURE AT 3 SHOCK FRONT ENERGY UTILIZATION NUMBER, A V/Vo PATENTEL 2 3,735,704

saw 05 0F .21

H2 1 o E 8 o 0' II n 2 O LBS. C-4, 195 OW SURFAC 10 LBS. C-4, ltb 0.8

10 LBS. A 60 TR ENCH SNOW 7L 0.6 0.4 k

moo

C-3 CHURCHILL TILL ATLAS 6C KEWEENAW SILT DEPTH RAHO A PATENTEB 2 I975 SHEET us OF 2 N- SCALED CRATER DEPTH pmgmgguhxzsmm 735,704

SHEET 09 [1F 21 I 5.0 lb. I

Lateral extent of bond strength destruction (gas bubble radius) l 0.4

l .7 g 7 0.2 7 f N SCALED CHARGE DEPTH I O l l 1 DEPTH RATIO A PATENTED 2 3.735.704

SHEET 10 0F 21 DIRECT'ON 0F ADVANCE FACE DO NOT REDUCE MINIMUM ORIENT PARALLEL to MAJOR JOlNT SYSTEM 5 H SLIDING RESISTANCE V 1 T14 13 l H Q I2 u n n n I0 4710 n u 3 M4 g l d w m E g LU -l E I 3 .1 C 2 .4 g E 2 Q a to 5 E2 UT I 0 Z I Q Ll-l I 7. 0 Q m i 3 5 I g; m

END LINE A PRIMACORD LOOP LINE OF SYMMETRY D FOR COMPOSITE BLASTS I SHORT PERIOD PRIMACORD LOOP BACK LINE E PRIMACORD LOOP DELAY NO.

CODE V-1 V-2 V-3 8-1 8-2 8-3 B4 B5 8-6 8-7 8-8 DIA. IN. 9.875 9.875 9.875 9.875 9.875 9.875 9.875 9.875 9.875 6.625 5.625

SUB. FT. 6.91 6.17 6.27 6.17 5.78 5.47 4.97 4.97 5.18 4.50 3.70

DEPTH ft. 40.91 40.17 40.27 40.17 39.78 39.74 38.97 38.97 39.18 38.50 37.70

PATENTEW 3,735,704

SHEET 1.5 OF 21 w 9.8 .7 .s s 4 .3 .2 0.: .08 .06 .04 .02 .01 0 I00 so a0 70 70 z 3 60 n 5O 5O 540 40 U 5 so so a.

IO l0 PREDOMINANT PARTICLE VOLUME, CU FT

Claims

1. In bench geometry blasting, where for the particular material to be blasted and explosive to be employed, the values of d, do, N, Delta o and E are known for a given weight of explosive charge W, d being any depth of burden of the charge; do being the depth of placement of a charge of the given weight which produces upon explosion of the charge maximum pressure rise within the material; N being the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed (as illustrated in accompanying FIG. 1); Delta o being the value of do/N for the given charge weight; and E being the value calculated from the formula N E cube root W using the value of N for the given weight; and where for the same particular material to be blasted and explosive to be employed, the values of dbo, N, and bo are known, dbo being the perpendicular distance from the vertical free face to the center of gravity of explosive charge which produces upon explosion of said charge maximum pressure rise within the material; N being as previously defined for the same charge weight used in determining dbo; and Delta bo being the value of d bo/N for the given charge weight; the improvement comprising controlling the trajectory of material formed as bench geometry surrounding a blast charge in response to explosion of the charge by; a. placing a charge of weight W at a vertical depth Delta v wherein Delta v dv/N wherein dv is the vertIcal depth; b. positioning said charge of weight W along a rearward extension of a line perpendicular to the bench free face at a burden Delta b wherein Delta b db/N wherein db is the burden distance and Delta b Delta v + Delta diff wherein Delta diff is a predetermined positive value, the trajectory being substantially in a vertical direction when Delta v is less than Delta b and substantially in the horizontal face direction when Delta b is less than v; and c. detonating the charge.

2. The method as defined in Claim 1, wherein the charge is placed at a vertical depth beneath the surface equal to db + ddiff ddiff being calculated from a Delta diff equalling ddiff/N and Delta diff is within the range of 0.02 - 0.20.

3. The method as defined in claim 1 wherein the known values and Delta diff are determined by conducting test crater and bench blasts.

4. In bench geometry blasting the method of controlling the trajectory of material surrounding a blast charge in response to explosion of the charge comprising: a. Conducting test crater blasts to determine values for do, N, and E for the surrounding material and type of explosive, where do is the depth of placement of a charge of known weight which produces upon explosion of the charge maximum pressure rise in the material; where N is the depth of placement of a charge of a known weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is placed and where E is calculated from the formula N E Cube Root W using the determined value of N and its known charge weight; b. Conducting test bench blasts to determine the value of Delta bo for the surrounding material and type of explosive, where Delta bo is dbo/N and dbo is the perpendicular distance from the free face of a bench geometry to the center of gravity of an explosive charge placed at a depth do which produces maximum pressure rise within the material; c. Placing a charge of weight determined by the formula do Delta o E Cube Root W at a depth of do+ ddiff beneath the upper surface of the material bench, ddiff being a predetermined positive value; d. Placing the charge along a rearward extension of the line of preferred trajectory a distance equal dbo, whereby trajectory is controlled to be substantially in the horizontal direction; and e. Detonating the charge.

5. The method as defined in claim 4, wherein ddiff is based on a diff in the range of 0.02- 0.20 and Delta diff ddiff/N.

6. A method according to claim 4 wherein dbo is determined by placing a series of test blasts of known weight at depths do and at various distances db from the the bench free face, detonating said charges and measuring the response of the material surrounding the blast to determine which burden distance produces the maximum doming without venting in the direction of the bench free face.

7. A method according to claim 4 wherein dbo is determined by placing a series of test blasts of known weight at depths do and at various distances db from the bench free face, detonating said charges and measuring the response of the material surrounding the blast to determine which burden distance produces the maximum volume of material broken per pound of explosive.

8. In bench blasting, the method of controlling the trajectory of the material surrounding the blast charge in response to explosion of the charge including preparing the bench face to have a disposition of substantially 45* with the horizontal, placing the charge along a line projecting perpendicular from substantially mid-point of the free face but within a range on either side of the free face equal to 70 percent of the free face length a distance from the free face substantially equal to the dbo for the material and explosive, dbo being the perpendicular distance from the vertical free face to the center of gravity of explosive charge which produces upon explosion of said charge maximum pressure rise within the material, spacing the charge a distance from the upper horizontal surface of the bench a distance equal to d, wherein d is any depth of the charge when d is determined from Delta o + diff + Delta inc and Delta is related to d by the formula Delta d/N, Delta o being the value of do/N for the given charge weight, diff being a predetermined positive value, inc being Delta bo minus Delta o, Delta bo being the value of dbo/N for the given charge weight, do being the depth of placement of a charge of the given weight which produces upon explosion of the charge maximum pressure rise within the material, N being the critical depth (as described in conjunction with FIG. 2), Delta diff being in the range of 0.05 to 0.25.

9. The method according to claim 8, wherein the distance from the free face is in the range of dbo to db where dbo is a function of Delta bo and db is a function of Delta bo - 0.15 and bo is related by dbo by the formula Delta bo dbo/N.

10. The method of autogenous blasting to produce a fine grain particle comprising: a. forming a crater by detonating a first explosive charge, the explosive set beneath the surface of earthen material to produce a muck pile backed against the free face formed by the blast; b. detonating at least one second explosive charge adjacent the first named charge, the distance of the second charge from the free face created by the first explosion being in the range where implosion occurs and the vortex is well developed and is directed toward the muck pile and corresponds to d values defined by Delta bo to Delta a where Delta d/N and Delta bo and Delta a are determined from test crater blasts, bo being the value of dbo/N for the given charge weight, dbo being the perpendicular distance from the vertical free face to the center of gravity of explosive charge which produces upon explosion of said charge maximum pressure rise within the material, N being the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is place, Delta a being the burden distance at which the velocity of the vortex is maximum.

11. The method as defined in claim 10 wherein the depth of the charge is controlled so as to predetermine breakage limits of the second blast whereby the angle of inclination Alpha of a subsequent blast is controlled within the range of Alpha o* to 45* .

12. The method of controlling the granulometry of material surrounding a charge of explosive in response to explosion of the charge comprising: a. conducting test crater blasts at various depths to determine the breakage limits of the material in response to the blasts; b. preparing a chart by plotting the slant distance to each of the types of fractures in the blasting failure process and to the doming limit from test crater blasts; c. establishing a grid over the crater formed by each test blast and measuring the particle size of the broken material touched by the grid; d. preparing a chart by plotting the variation of the predominate partiCle size with various charge depths at scaled depth ratios Delta ; e. determining in the range Delta d to Delta o from the chart of (d) the value in the controlling burden direction at which the desired predominate particle size can be achieved, d is the Delta value at which doming begins and Delta o is the value of do/N for the given charge weight, do being the depth of placement of a charge of the given weight which produces upon explosion of the charge maximum pressure rise within the material, and N being the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed; or in the range Delta o to Delta equals 0 the value at which the desired particle size can be achieved where predominant particle size from autogenous blasting ranges from near zero to that measured at Delta o of the crater tests; f. decreasing the crater chart value (e) by subtracting for bench geometry a Delta increment adjustment ranging linearly from a maximum at Delta bo- Delta o for a controlling burden of magnitude Delta o to zero for a controlling burden Delta a or less or for a controlling burden Delta ss or greater, Delta increment being Delta bo minus Delta o, Delta bo being the value of dbo/N for the given charge weight, dbo being the perpendicular distance from the vertical free face to the center of gravity of explosive charge which produces upon explosion of said charge maximum pressure rise within the material, Delta a is the Delta value at which the volume of the apparent crater is maximum, and Delta ss being the Delta value at which cratering begins; g. placing the charge at a distance from the controlling burden toward the face of the bench corresponding to the adjusted Delta value; h. placing the charge at a distance from the non-controlling free face at the crater test determined value; and i. detonating the charge.

13. The method of stability control bench blasting, including: a. conducting test crater blasts and preparing a chart by plotting the slant distance to limits of each of the types of fractures in the blasting failure process and to the doming limit, by plotting the slant distances to the crater lip against charge depth and the zone of bond strength destruction against charge depth, R cracks defining the limits of extreme rupture and by plotting the variation in predominant particle size against charge depth from the parameters determined from said blasts; b. selecting a predetermined limit part which the material in which the blasts are conducted is not to be affected; c. progressively setting and detonating explosive charges in the direction approaching said limit, each successive charge being decreased in Delta b value and increased in Delta v value so as to progressively increase the Delta v- Delta b difference approaching said limit, the Delta b value being determined from the cratering results using the relation b/N, where b is the bench burden in feet and N is the distance in feet at which cratering begins for the bench charge, the Delta v value being determined from the relation dc/N, where dc is the distance beneath the top of bench in feet to the bench charge; and d. the placement of the charge being such that the limits of extreme rupture as defined in said chart do not for any given blast extend beyond the predetermined limit.

14. The method as defined in claim 13, wherein the burden of any charge approaching said limit is of a distance db controlled by Delta , and Delta is in the range Delta 0 -0.10 and Delta 0 -0.20, and where Delta db/N.

15. The method as defineD in claim 13, further including the step of placing rock bolts in the material prior to blasting to reinforce the material beyond said limit.

16. The method as defined in claim 13, further including digging breakage limit trenches in the surface of the surrounding material along the line of the predetermined limit.

17. The method as defined in claim 1 wherein the charge is placed at a controlling burden from the vertical free face equal to dv +d diff being calculated from a Delta diff equalling ddiff/N and Delta diff is within the range of 0.20 - 0.20.

18. The method as defined in claim 3 wherein said test crater and bench blasts include: a. conducting cratering tests so as to measure the limits of R cracks, I cracks, O cracks, shock slabs, rebound slabs, crater and doming; b. measuring time, velocity, and duration of massive ground motion for each of the charges of said cratering tests and determining the variation with scaled charge depth for the series of charges for a given type, shape, weight and depth of charge; c. excavating the craters formed in said cratering tests so as to measure the limits of the bond strength destruction zone, intermediate zone, and the barrier zone and to determine the granulometry, size and shape of particles in each zone and for each blast, and summarizing the variation for the series of blasts with scaled charge depth; d. conducting test bench blasts so as to: i. observe the effect of the second free face upon breakage limits, particle size, and volume of material broken per pound of explosive; ii. determine the variation in time, velocity and duration of massive ground motion in the Delta v direction towards the top of the bench and in the Delta b direction towards the face of the bench at various values of Delta v - Delta b, and iii. determine the scaled slant distance to the doming limit at various values of Delta b, the controlling burden; e. determine the Delta increment adjustment from said test bench blasts and applying the adjustment to correct fracture, crater, doming limits, particle size, granulometry and shape to the geometry of bench blasting; f. utilizing a chart plotting and slant distances to the doming limit for a given blast to predetermine excavation limits in bench blasting to determine Delta v given Delta b, or to determine Delta b given Delta b so as to predetermine the position and inclination of the free face prior to a bench blast or successive bench blasts; g. predetermining the time, velocity, duration and trajectory of a blast in the Delta b direction towards the face of the bench and the Delta v direction towards the top of the bench so as to achieve the desired throw in either or both directions, such determination of the throw being based upon the results of the crater tests; and h. predetermining excavation limits as in (a) and simultaneously controlling trajectory and granulometry towards the top and towards the face of the bench so as to predetermine both trajectory and granulometery from results of the crater and bench tests.

19. A method of trajectory control blasting comprising: a. conducting crater and bench blast tests to predetermine limits of fracturing, cratering and doming in bench blasting and so as to determine the variation in time, velocity and duration of massive ground motion with variation in controlled burden and variation in Delta difference, Delta v- Delta b, wherein Delta v dv/N wherein dv is the vertical depth and N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed, and Delta b db/N wherein db is the burden distance; b. creating A free face at a predetermined angle perpendicular to the angle of desired trajectory of a subsequent blast by placing and detonating a charge of known weight at a burden, Delta b, and depth of center of gravity of the explosive charge, Delta v, at which the inclination of a line from the center of gravity of the charge to the doming limit of the bench test produces the desired inclination; c. determining Delta v, Delta b, and Delta v- Delta b from cratering and bench tests and placing the charge so that: i. the desired proportions of massive ground motion both in the Delta v direction towards the top of the bench and in the Delta b direction towards the face of the bench are predetermined to produce the desired trajectory, granulometry, or both, and ii. so that the time, velocity and duration of massive ground motion will be such as to produce the desired throw; d. placing the charge on the rearward extension of the line of desired trajectory at a distance Delta b so as to obtain the desired breakway velocity in a direction normal to the free face and as indicated by the bench tests, and so as to predetermine the time, velocity and duration of massive ground motion in the Delta v direction toward the top of the bench; and e. detonating the charge.

20. A method of maximizing the quantity of fine material from a blast including: a. conducting crater blast tests so as to determine limits of R cracks, I cracks, O cracks, slabs, rebound slabs, and limits both of the apparent crater and the true crater, and to determine the variation in predominant particle size with scaled charge depth and the time, velocity and duration of massive ground motion, including excavating the craters to observe the limits of bond strength destruction, the intermediate zone, and the barrier zone, and determining by observation of cratering results the depth at which the explosion cavity collapses and a ground motion vortex action begins; b. preparing a chart by plotting the slant distances to limits of each of the types of fractures in the blasting failure process and to the doming limit, by plotting the slant distances to the crater lip against charge depth and the zone of bond strength destruction against charge depth, R cracks defining the limits of extreme rupture and by plotting the variation in predominant particle size against charge depth from the parameters determined from said blasts; c. preparing an opening cut or free face by blasting so as to predetermine the inclination of the sides within the range of 45* from the horizontal to vertical and so as to produce a muckpile to inhibit ground motion of subsequent blasts; d. placing a charge of given type of explosive of given weight, W, behind the face so that the distance Delta v beneath the top of the bench is in the range of Delta o-0.02 to Delta o-0.10 and the distance Delta b perpendicular to the face is in the range Delta Delta mb to ( Delta a + Delta o)/2 where Delta a is the charge depth at which the volume of the apparent crater is maximum, Delta o is the charge depth at which the volume of the true crater is maximum, Delta mb is the charge depth at which the slant distance from the charge to the limit of bond strength destruction is maximum; the weight of the charge W, the depth of charge dc, and the burden b being determined by the equations i. N E Cube Root W wherein N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed, and E is the value calculated using the value of N for the given weight, ii. Delta b b/N,and Delta v dc/N, iii. dc Delta E Cube Root W, and iv. V/W E3ABC, wherein A V/Vo, V being the crater volume, Vo being the crater volume at optimum charge depth d, B Vo/N3, and C (V/Vob). Co wherein Co (V/W bench)/(Vo/W crater); e. placing said charge such that a vortex action is produced as a result of implosion and ground motion following collapse of the explosion cavity, and the venting gas bubble is directed into the muckpile so as to develop a scouring action between particles and so as to minimize excessive flyrock which otherwise would occur, said vortex action occurring within the range Delta 0 to Delta Delta o, the venting gas bubble being controlled in the direction of Delta b, if Delta v is sufficiently larger than Delta b, and the scouring action between particles is developed for the particular controlling value of b if the duration of the action equals that measured for a cratering blast of the same explosive at the same Delta value and charge shape; and f. detonating the charge.

21. The method as defined in claim 20 including a. directing the vortex action into the muckpile by assuring that ground motion towards the opening cut or inclined free face will predominate over that in the vertical direction by predetermining v to exceed Delta b and defining the Delta b-Delta v difference to be within the limitations: b is greater than Delta mb and less than ( Delta a + Delta o)/2 and Delta v is greater than Delta o-0.02 and less than or equal to Delta 0-0.10; b. predetermining the particle size attributable to ground motion in the Delta b direction to be smaller than that attributable to ground motion in the Delta v direction due to: i. the scouring action within the vortex attributable to the greater velocity near the center than the edges of the vortex, and ii. containment of the vortex due to the Delta v- Delta b difference; and c. predetermining the particle size in the Delta b and Delta v directions using a chart plotting predominant particle size, zones and charge depth from test crater blasts.

22. The method as defined in claim 20 including: a. determining the spacing between rows of holes of a multiple hole blast by: controlling the position and inclination of the free face; predetermining the excavation limit from the preceding row of holes using results of the cratering tests and plotting a chart of the variation in slant distance to crater, cracks and doming limits against charge depth; and placing the charge behind the free face next to be created so that Delta b is greater than mb and Delta b is less than (a + Delta o)/2 and Delta v is greater than Delta o-0.02 and less than or equal to Delta o-0.10; b. minimizing random ground motion by controlling the delay interval between successive rows of holes so that the velocity of massive ground motion in the vertical direction will not exceed that as determined from cratering blast tests at a charge depth for the range of Delta v previously specified; c. minimizing random ground motion by detonating charges of successive rows in such a sequence that a barrier mass determined by the Delta diff of thickness not less than 1.4N exists or that the barrier mass is destroyed by detonating charges in it at the same instant as the row blast holes approaching the barrier mass reaches a distance of 1.4N or less; d. promoting the vortex action between successive rows of holes so that the delay interval between successive rows will not be less than the duration of ground motion as determined by a crater blast test for a charge of the same shape, type and weight of explosive at the same controlling burDen; e. minimizing excessive packing of the muckpile by varying the angle of inclination Alpha of the vortex within the range 0 to 45* from the horizontal by predetermining the inclination of successive free faces by predetermining with the controlling burden the slant distance from the charge to the doming limit at the top of the bench; and f. increasing the proportion of fine material available to the vortex action by controlling the spacing Delta s between holes of a given row within the range Delta s Delta b to Delta s 1.4 Delta b where Delta b previously has been defined as being in the range Delta mb to ( Delta a + Delta o)/2, which are approximate limits of the bond strength destruction zone as determined from the test crater blasts.

23. The method as defined in claim 12 wherein said test crater and bench blasts are conducted to: a. determine parameters A and B using test crater blasts wherein A V/Vo wherein V the crater volume and V0 the crater volume at optimum charge depth d, and B Vo/N3; b. determine various values of parameter C using test bench blasts for various heights of bench, burden and Delta v-Delta b difference, wherein Delta v dv/N wherein dv is the vertical depth and Delta b db/N wherein db is the burden distance, and C (V/Vob) . Co wherein Co (V/W bench)/(Vo/W crater) wherein Vob is the optimum crater volume in the burden direction and the Delta and Vo are the volume of the crater in the depth direction and burden direction, respectively; and c. determine the geometry of the bench for a given explosive, weight and shape of charge from measurements of breakage limits and particle size in bench blasting and identified by the product control index number, ABC of the equation V/W E3 ABC, where E is calculated from the formula N E Cube Root W.

24. A method of multiple row product control blasting consisting of: a. conducting crater and bench blast tests to predetermine limits of fracturing, cratering and doming in bench blasting and so as to determine the variation in time, velocity and duration of massive ground motion with variation in controlling burden and variation in Delta difference, Delta v- Delta b, wherein Delta v dv/N wherein dv is the vertical depth and N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed, and Delta b db/N wherein db is the burden distance; b. creating successive free faces at a predetermined angle by placing a charge at a depth Delta v and a burden Delta b and at a Delta diff, Delta diff being a predetermined positive value, the trajectory being substantially in the vertical direction when the burden equals Delta v + Delta diff and substantially in the horizontal direction when the depth equals Delta b + Delta diff, thereby allowing predetermining of the controlling burden for the succeeding rows of holes; c. predetermining from results of the crater and bench tests from the proper delay interval between blasts using time, velocity and duration of ground motion measurements so that motion of a given row does not begin before motion of the previous row is complete; d. placing a charge or series of charges with respect to the top of the bench and the face of the bench so as to predetermine for each charge the proportions of massive ground motion in each of the depth and burden direCtions according to the granulometry desired; and e. successively detonating charges of the series at the predetermined delay interval between charges.

25. A method of stability control blasting including: a. conducting crater and bench blast tests to predetermine limits of fracturing, cratering and doming in bench blasting and so as to determine the variation in time, velocity and duration of massive ground motion with variation in controlling burden and variation in Delta difference, Delta v- Delta b, wherein Delta v dv/N wherein dv is the vertical depth and N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed, and Delta b db/N wherein db is the burden distance; b. defining a predetermined limiting part which the material in which the blasts are conducted is not to be affected, and defining a stability control zone between the limiting part in the main body to be excavated such that breakage limits and doming due to blasting within said stability control zone will not extend beyond limits of the stability control zone; c. progressively setting and detonating explosive charges within the stability control zone approaching the limiting part so that the Delta v- Delta b difference progressively increases so as to progressively suppress massive ground motion towards the top of the bench and so as to progressively increase the velocity of ground motion towards the face of the bench, Delta v dv/N wherein dv is the vertical depth and N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is placed, and Delta b db/N wherein db is the burden distance; and d. placing the charge such that Delta v exceeds the slant distance to R cracks or to the doming limit, and rebound cracks do not for any given blast extend beyond the predetermined limits.

26. A method of stability control blasting including: a. conducting bench blast tests to predetermine limits of fracturing, cratering and doming in bench blasting and so as to determine the variation in time, velocity and duration of massive ground motion with variation in controlling burden and variation in Delta difference, Delta v- Delta b, wherein Delta v dv/N wherein dv is the vertical depth and N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed, and Delta b db/N wherein db is the burden distance; and to determine the Delta v- Delta b difference at which massive ground motion towards the top of the bench is insufficient to cause blasting damage at the collar of the borehole in row blasting; b. measuring the time, velocity and duration of massive ground motion in the Delta b direction at the Delta v- Delta b difference, as defined in step (a); c. progressively setting and detonating charges in the direction of mining advance based upon time, velocity and duration measurements of the bench blast tests so that ground motion toward the top of the bench is not predetermined by the duration of horizontal ground motion of the previous charge; and d. placing the charge such that Delta b equals the burden determined experimentally for the Delta v- Delta b difference, determined in step (a), and the delay interval between successive charges is such that horizontal ground motion from successive charges does not affect vertical ground motion, and the weight of explosive detonatEd per delay does not exceed that for which said Delta v- Delta b was determined.

27. The method as defined in claim 25 wherein the Delta v-Delta b difference is determined within the range Delta v is greater than 1.0 and less than 1.4, and Delta b is within the range Delta o-0.10 and Delta o-0.20.

28. In bench geometry blasting, the method of controlling the trajectory of material surrounding a blast charge in response to explosion of the charge comprising: a. Conducting test crater blasts to determine values for do, N, and E for the surrounding material and type of explosive, where do is the depth of placement of a charge of known weight which produces upon explosion of the charge maximum pressure rise in the material; where N is the depth of placement of a charge of a known weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is placed; and where E is calculated from the formula N E Cube Root W using the determined value of N and its known charge weight, said test crater blasts being carried out by setting charges of known weight, shape and type of explosive at various depths, detonating charges, measuring the limits of R cracks, I cracks, O cracks, shock slabs, rebound slabs, cratering and doming on the surface; and excavating the crater so as to determine the shape of the true crater, limits of bond strength destruction zone, the intermediate zone, barrier zone and transition limits; b. Conducting test bench blasts to determine the value of Delta bo for the surrounding material and type of explosive, where Delta bo is dbo /N and dbo is the perpendicular distance from the free face of a bench geometry to the center of gravity of an explosive charge placed at a depth do which produces maximum pressure rise within the material; c. Placing a charge of weight determined by the formula do Delta o E Cube Root W at a depth do + ddiff beneath the upper surface of the material bench, ddiff being a predetermined positive value; d. Placing the charge along a rearward extension of the line of preferred trajectory a distance equal dbo, whereby trajectory is controlled to be substantially in the horizontal direction; and e. Detonating the charge.

29. In bench geometry blasting, the method of controlling the trajectory of material surrounding a blast charge in response to explosion of the charge comprising: a. Conducting test crater blasts to determine values for do, N, and E for the surrounding material and type of explosive, where do is the depth of placement of a charge of known weight which produces upon explosion of the charge maximum pressure rise in the material; where N is the depth of placement of a charge of a known weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is placed and where E is calculated from the formula N E Cube Root W using the determined value of N and its known charge weight, said test crater blasts being performed by detonating a series of charges of given type and known shape and weight at various depths measuring the ground rise to determine the time, velocity and duration of ground motion to differentiate between effects attributable to the arrival of the shock wave, the pressure rise in the material, and the venting of the gas bubble; b. Conducting test bench blasts to determine the value of Delta bo for the surrounding material and type of explosive, where Delta bo is (dbo/N) and dbo is the perpendicular distance from the free face of a bench geometry to the center of gravity of an explosive charge placed at a depth do which produces maximum prEssure rise within the material; c. Placing a charge of weight determined by the formula do Delta o E Cube Root W at a depth do + ddiff beneath the upper surface of the material bench, ddiff being a predetermined positive value; d. Placing the charge along a rearward extension of the line of preferred trajectory a distance equal dbo, whereby trajectory is controlled to be substantially in the horizontal direction; and e. Detonating the charge.

30. In bench geometry blasting, the method of controlling the trajectory of material surrounding a blast charge in response to explosion of the charge comprising: a. Conducting test crater blasts to determine values for do, N, and E for the surrounding material and type of explosive, where do is the depth of placement of a charge of known weight which produces upon explosion of the charge maximum pressure rise in the material; where N is the depth of placement of a charge of a known weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is placed; and where E is calculated from the formula N E Cube Root W using the determined value of N and its known charge weight; b. Conducting test bench blasts to determine the value of Delta bo for the surrounding material and type of explosive, where Delta bo is (dbo/N) and dbo is the perpendicular distance from the free face of a bench geometry to the center of gravity of an explosive charge placed at a depth do which produces maximum pressure rise within the material, said test crater and bench blasts being conducted to: i. determine parameters A and B using test crater blasts wherein A (V/Vo) wherein V the crater volume and Vo the crater volume at optimum charge depth d, and B (Vo/N3); ii. determine various values of parameter C using test bench blasts for various heights of bench, burden and Delta v-Delta b difference, wherein Delta v (dv/N) wherein dv is the vertical depth and Delta b (db/N) wherein db is the burden distance, and C (V/Vob) . Co wherein Co (V/W bench)/(Vo/W crater); iii. determine the geometry of the bench for a given explosive, weight and shape of charge from measurements of breakage limits and particle size in bench blasting and identified by the product control index number, ABC of the equation (V/W) E3 ABC, where E is calculated from the formula N E Cube Root W; c. Placing a charge of weight determined by the formula do Delta o E Cube Root W at a depth do + ddiff beneath the upper surface of the material bench, ddiff being a predetermined positive value; d. Placing the charge along a rearward extension of the line of preferred trajectory a distance equal dbo, whereby trajectory is controlled to be substantially in the horizontal direction; and e. Detonating the charge.

31. In bench geometry blasting, the method of controlling the trajectory of material surrounding a blast charge in response to explosion of the charge comprising: a. Conducting test crater blasts to determine values for do, N, and E for the surrounding material and type of explosive, where do is the depth of placement of a charge of known weight which produces upon explosion of the charge maximum pressure rise in the material; where N is the depth of placement of a charge of a known weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the chaRge is placed; and where E is calculated from the formula N E Cube Root W using the determined value of N and its known charge weight; b. Conducting test bench blasts to determine the value of Delta bo for the surrounding material and type of explosive, where Delta bo is (dbo/N) and dbo is the perpendicular distance from the free face of a bench geometry to the center of gravity of an explosive charge placed at a depth do which produces maximum pressure rise within the material; c. Conducting crater blasts so as to determine the breakaway velocity at Delta o as to identify granulometry representative of each of the bond strength destruction zone, the intermediate zone and the barrier zone surrounding the charge; d. Conducting bench blasts to determine Delta bo and Delta increment adjustment Delta bo- Delta o, by placing a charge of substantially spherical shape at depth, Delta o, as determined by the crater blasting and varying the burden in the range Delta b greater than Delta o to determine the Delta increment, Delta bo- Delta o where (V/W) is maximum and the breakaway velocity towards the face of the bench equals that toward the top of the bench; e. Correcting cratering granulometry, limits of the bond strength destructive zone, the intermediate zone, the barrier zone and limits of the crater to the geometry of bench blasting; f. Placing a charge of weight determined by the formula do Delta o E Cube Root W at a depth do + ddiff beneath the upper surface of the material bench, ddiff being a predetermined positive value; g. Placing the charge along a rearward extension of the line of preferred trajectory a distance equal dbo, whereby trajectory is controlled to be substantially in the horizontal direction; and h. Detonating the charge.

32. A method of stability control blasting including: a. Conducting crater and bench blast tests to predetermine limits of fracturing, cratering and doming in bench blasting and so as to determine the variation in time, velocity and duration of massive ground motion with variation in controlling burden and variation in Delta difference, Delta v- Delta b, wherein Delta v (dv/N) wherein dv is the vertical depth and N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge fractures on the surface of the material in which the charge is placed, and Delta b (db/N) wherein db is the burden distance; b. Defining a predetermined limiting part which the material in which the blasts are conducted is not to be affected, and defining a stability control zone between the limiting part in the main body to be excavated such that breakage limits and doming due to blasting within said stability control zone will not extend beyond limits of the stability control zone; c. Progressively setting and detonating explosive charges within the stability control zone approaching the limiting part so that the Delta v- Delta b difference progressively increases so as to progressively suppress massive ground motion towards the top of the bench and so as to progressively increase the velocity of ground motion towards the face of the bench, Delta v (dv/N) wherein dv is the vertical depth and N is the depth of placement of a charge of the given weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is placed, and Delta b (db/N) wherein db is the burden distance; d. Placing the charge such that Delta v exceeds the slant distance to R cracks or to the doming limit, anD rebound cracks do not for any given blast extend beyond the predetermined limits; e. Excavating a breakage limit trench, one wall of which coincides with said limiting part; f. Placing rock bolts into the permanent wall along the line of the limiting part; and g. backfilling the breakage limit trench prior to production blasting so that the fill material both acts as a shock dampening substance and prevents fractures from developing beyond the predetermined limit.

33. In bench geometry blasting, the method of controlling the trajectory of material surrounding a blast charge in response to explosion of the charge comprising: a. Conducting test crater blasts to determine values for do, N, and E for the surrounding material and type of explosive, where do is the depth of placement of a charge of known weight which produces upon explosion of the charge maximum pressure rise in the material; where N is the depth of placement of a charge of a known weight which first begins to produce upon explosion of the charge a crater on the surface of the material in which the charge is placed; and where E is calculated from the formula N E Cube Root W using the determined value of N and its known charge weight; b. Conducting test bench blasts to determine the value of Delta bo for the surrounding material and type of explosive, where Delta bo is (dbo/N) and dbo is the perpendicular distance from the free face of a bench geometry to the center of gravity of an explosive charge placed at a depth do which produces maximum pressure rise within the material; c. Placing a charge of weight determined by the formula do Delta o E Cube Root W at a depth do beneath the upper surface of the material bench; d. Placing the charge along a rearward extension of the line where trajectory is to be substantially inhibited a distance equal to dbo + ddiff, ddiff being a predetermined positive value, whereby trajectory is controlled to be substantially in the vertical direction; and e. Detonating the charge.