Designing Blast Patterns Using Empirical Formulas
Information Circular 8550Designing Blast PatternsUsing Empirical FormulasA Comparison of Calculated Patterns With PlansUsed in Quarrying Limestone and Dolomite,With Geologic ConsiderationsBy Joseph M. PuglieseTwin Cities Mining Research Center, Minneapolis, Minn . US Department of InteriorOffice of Surface MiningReclamation and EnforcementKenneth K. EltschlagerMining/Explosives Engineer3 Parkway CenterPittsburgh, PA 15220Phone 412.937.2169Fax 412.937.3012Keltschl@osmre.govUNITED STATES DEPARTMENT OF THE INTERIORRogers C. B. Morton, SecretaryBUREAU OF MINESE1burt F. Osborn, Director
This publication has been cataloged as follows:Pugliese, Joseph MDesigning blast patterns using empirical formulas: a comparison of calculated patterns with plans used in quarryinglimestone and dolomite, with geologic considerations.[Washington] U.S. Dept. of the Interior, Bureau of Mines (1972]33 p. illus., tables. (U.S. Bureau of Mines, Information circular8550)Includes bibliography.1. Blasting-Mathematical models.II. Title. (Series)TN23.U71no. 8550I. U.S. Bureau of Mines.621.06173U.S. Dept. of the Int. LibraryFor sale by the Superintendent of Documents, U.S. Government Printing OfficeWashington, D.C. 20402 ·Price 45 centsStock Number 2{04-1145Catalog No. 12S.l17:85ro
CONTENTSAbstract.1Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12Composition and origin of limestone and dolomite.Definition of major geologic features in these rock types observed to3influence explosive blasting.3Production blast terminology. . . . . . . . . . . . . . . . . . . . . . .Empirical formulas that may be applied to drilling and blastingpattern design.Calculation of burden, B, from equation 1. . . . Calculation of spacing, S, from equation 2 .·.Calculation of hole length, H, from equation 3.Calculation of subdrilling length, J, from equation 4.Calculation of collar distance, T, from equation 5.Direct comparisons of blast plans calculated by the empirical formulaswith actual examples of blasting patterns used by the No.No.No.No.No.No.No.No.No.1 explosive blasting details .2 explosive blasting details . .3'explosive blasting details . . . .4 explosive blasting details . . .5 explosive blasting details .6 explosive blasting details . . .7 explosive blasting details . . . . 8 explosive blasting details . · . 9 explosive blasting details . .10 explosive blasting details . . 11 explosive blasting details . .12 explosive blasting details .SUinllla ry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .References . . . . . . . . . . . . 2.Bench cross section view showing De, B, H, J, T, and L. . . Generalized blasting patterns showing B, S, b, and s.45TABLES1.2.3.Calculation sheet-drill pattern dimensions for average and alternative blasting conditions.Blasting pattern dimensions for Ohio, Adams County, Quarry No. 1.Blasting pattern dimensions for Ohio, Highland County,911Quarry No. 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124.Blasting pattern dimensions for Ohio, Crawford County,Quarry No. 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
iiTABLES--Continued5.Blasting pattern dimensions for Wisconsin, Waukesha County,6.Blasting pattern dimensions for Wisconsin, Waukesha County,7.Blasting pattern dimensions f?r Wisconsin, Waukesha County,8.Blasting pattern dimensions for Wisconsin, Milwaukee County,9.Blasting pattern dimensions for Wisconsin, Milwaukee County,Quarry No. 4 . . . . . . . . . . . . -. Quarry No, 5 . . . . . . . . . . . . . . . Quarry No. 6 . . . . . . . . . . . .Quarry No. 7 . . . . . .Quarry No.8.161820222310.Blasting pattern dimensions for Wisconsin, Racine County,Quarry No . 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2511.2712.Blasting patt:ern dimensions for Minnesota, Olmsted County,Quarry No. 10 . . . .Blasting pattern dimensions for Minnesota, Fillmore County,Quarry No. 11 . . . . . . . . . . . . .2813.Blasting pattern dimensions for Minnesota, Wabasha County,Quarry No. 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
DESIGNING BLAST PATTERNS USING EMPIRICAL FORMULASA Comparison of Calculated Patterns With Plans Used in QuarryingLimestone and Dolomite, With Geologic ConsiderationsbyJoseph M. Pugliese 1ABSTRACTThis work was done by the Bureau of Mines to provide quarry operatorswith an uncomplicated, first-approximation method for designing blastpatterns, considering geologic structure, and to show the valid use of thetechnique by comparing drill and blast pattern dimensions used in the quarrywith those determined by the presented method. The author visited 12 limestone and dolomite,quarries in Ohio (Adams, Crawford, and Highland Counties),Wisconsin (Milwaukee, Racine, and Waukesha Counties), and Minnesota (Fillmore,Olmsted, and Wabasha Counties); observed the blasting practices; studied themajor geologic features; and after discussion with the quarry managers,foremen, and blasters, compared the quarry blasting patterns with those ascalculated by the empirical formulas (after R. L. Ash), with geologic structural considerations. When geologic structure such as bedding, jointing,folding, and caves, as well as explosive properties and field performancecharacteristics are accounted for in a manner suggested by the research, thepresented empirical formulas may be used as a good first approximation. Theinclud d steps in planning a blast design and generalized blast patternsshould be of help to the quarry operator. Design changes are recommended forthose q arries where problems are occurring.INTRODUCTIONThe Bureau of Mines has been conducting field studies of explosive blasting in rock for a number of years. Concerning the topic of this paper, a fewof the studies are reported here. Atchison and Pugliese (,2)? in theircomparative studies of explosives in limestone with tight joints, found thatrepeated blasting in an area opened the tight separations in the rock. Theirresults reflected the effect of this joint opening. Nicholls and Duvall Q])studied the effect a charge diameter has on explosive performance. A recentstudy {14) showed horizontal bedding without or with conspicuous jointing,folds, faults, caves, and filled joints influence blasting and mining in limestone and dolomite quarries. The quarry operators attempt to minimizeGeophys ic is t.aunderlined numbers in parentheses refer to items in the list of referencesat the end of this report.l
2- detrimental geologic effects and maximize beneficial geologic effects. Outsideof the Bureau, other investigations are noteworthy. Belland ) concludedthat geologic structural controls on rock fragmentation upon explosiveblasting do exist and that explosive blast patterns should be designed to makeoptimum use of geologic controls. Ash Q) has developed five basic empiricratios for designing blasts. Ash and others ( ) investigated further todetermine conditions for optimizing spacing of simultaneously initiatedmultiple explosive columns. Ash's recent study ( ) demonstrates the validityof his earlier work on determining blasting relationships useful for estimating blast pattern dimensions. Grimshaw and Watt (11) commented on innovationsin the quarry blasting field being introduced to a8;ist the quarry operator inproducing stone with improved economy, safety, and efficiency. They note somepossible benefits to be associated with shallow face working which emphasizethe interdependence of the drilling, blasting, and materials-handlingoperations.While the author was conducting his study (14), he noted many quarryoperators were not cognizant of the work mentioned above. There was a lackof awareness of uncomplicated, first-approximation blast pattern designcriteria, including geologic considerations. In many instances, blastpatterns providing satisfactory results had been developed on a trial anderror basis, which is costly in time and money. The author felt the needfor a report containing: Simplified formulas (after Ash) 3 that may be used inmaking first approx:f mations of drilling and blasting patterns, with geologicconsiderations; suggested sequence of steps in planning the blast design;generalized blasting pattern views that may be used; and direct comparisonswith patterns used in the quarry.In collecting information for this report, the author visited 12 quarriesin Ohio (Adams, Crawford, and Highland Counties), Wisconsin (Milwaukee, Racine,and Waukesha Counties), and Minnesota (Fillmore, Olmsted, and Wabasha Counties); observed the blasting practices; studied the major geologic features;and after discussion with the quarry managers, foremen, and blasters, comparedthe blast patterns calculated by empirical formulas to quarry blastingpatterns producing satisfactory results, with geology considered in the blastdesigns. Design changes were recommenced for those quarries where problemswere occurring and where the 'calculations suggested a change.In this report, explosive ingredients, properties, and field performancecharacteristics are included only when necessary. The reader is referred toDick ( ) and Yancik (15) if more extensive information is desired.ACKNOWLEDGMENTSThe author wishes to thank David E. Fogelson, supervisory geophysicist atthe Bureau of Mines, Twin Cities Mining Research Center, for his suggestionsand guidance in the early phase of this study. The author also thanks3Use of these formulas is by the author's choice and does not imply endorsement by the Bureau of Mines. Other formulas are available in publications(10,.!1)·
3Richard A. Dick, mLnLng engineer at this Center, and Richard L. Ash of theUniversity of Missouri at Rolla for their helpful suggestions in interpretingthe data.The author wishes to acknowledge the generous cooperation of those quarryoperators who participated in this study by permitting access to their property and providing much of the data that made this report possible.COMPOSITION AND ORIGIN OF LIMESTONE AND DOLOMITEAccording to Bowles (1), limestone is composed mainly of calciumcarbonate (CaC03 ). The rock is known as a high-calcium limestone if themagnesium carbonate content is small. The rock is called a magnesium ordolomitic limestone if 10 percent or more of magnesium carbonate is present.When the magnesium carbonate content approaches 45 percent, the rock is knownas dolomite, the double carbonate of calcium and magnesium CaMg(C03 ) 2 Limestone consists chiefly of calcium carbonate shells and skeletons oforganisms that inhabited oceans and lakes. Uncounted generations of theseorganisms lived and died to leave their shell and skeletal remains accumulatedon sea and lake floors. Such shell supplies are supplemented by chemicallyprecipitated calcium carbonate and, according to some geologists, chemicallyprecipitated magnesium carbonate. During later geologic ages, beds of othermaterial were deposited over the carbonates and thus caused pressures thatgradually consolidated the carbonates into limestone. Limestones can containlarge amounts of impurities such as clay and silica.Opinions differ on the formation of dolomite. Some geologists believethat dolomite was formed directly from precipitation of calcium and magnesiumcarbonate while others hold that dolomite was formed from limestone throughthe replacement of some of the calcium by magnesium.The individual limestone and dolomite layers range from a fraction of aninch to many feet in thickness. Massive strata of uniform texture indicaterelatively long periods of uniform conditions of sedimentation. A beddingplane is introduced when these conditions are temporarily changed. Ingeneral, each bedding plane marks the termination of one deposit and thebeginning of another.DEFINITION OF MAJOR GEOLOGIC FEATURES IN THESE ROCK TYPESOBSERVED TO INFLUENCE EXPLOSIVE BLASTINGThe following major geologic features were observed to affect explosiveblasting in limestone and dolomite quarries. The terminology used here isthat of the Dictionary of Geological Terms prepared by the American GeologicalInstitute (!).Bedding is a collective term signifying existence of beds. A bed is thesmallest division of a stratified series and is marked by a reasonab.ly welldefined divisional plane separating its neighbors above and below.
4Jointed bedding is composed of fractures (joints) in the rock, generallyvertical or transverse to bedding, along which no appreciable movement of rockhas occurred. A joint set is a group of approximately parallel joints. Ifclay and/or mud accumulate in an open joint, i t will be considered as a filledjoint. The filled joint may have a few discontinuous open channels.Folded bedding is marked by a bend in the strata. In this report, bedding is considered folded when this feature is present to a major extentwithin the confines of and in relation to the blast or quarry area. Faultedbedding is characterized by a fracture in the rock with a displacement of thesides relative to one another parallel to the fracture.An unconformity is a surface of erosion or nondeposition, usually theformer, that separates the younger strata from older rocks. A bed is unconformable when it does not succeed the underlying strata in immediate orderof age.A cave is a natural cavity, chamber, or series of chambers beneath thesurface of the earth. Such underground openings are usually produced bysolution of limestone and dolomite.PRODUCTION BLAST TERMINOLOGYThe following list of blasting-pattern dimension symbols will be used inthis report. The symbolsare the same as those usedby Ash (2-3). The benchcross se tion view (fig. 1)and the plan view of generalized blasting patterns(fig. 2) should facilitateunderstanding of the symbols.The blasting patterns shownin figure 2 can be used'as afirst approximation. Inmultirow blasting (fig. 2,plans A-E), a row is considLered as an array of two ormore holes such that a linedrawn through the holecenters is perpendicular toChargethe final rock displacementdirection, indicated by thearrow on each plan. Inplans F and G (fig. 2), theFloorone array of holes will beconsidered as a row.JFIGURE 1. - Bench Cross Section View Showing De, B, H,J, T, and L (2-3).
5tt ue\elll.!!llll!llarerT eliiilri!!fl)illiiiiteus Ii Ir.t2 I I 3BOX CUT,EXPANDING FLAT BOTTOMED VPLAN BBOX CUT, EXPANDING VPLAN At I 2CORNER CUT, ECHELONPLAN CCORNER CUT, ECHELONPLAN D.1'TB'-*- 4 3 '{, · , 5 4 3 "" - 2 5 4 CORNER CUT, ECHELONPLANE.1'I1l jJI! I! I ,il! . .,l l : rn:J;M-· ! Il ;! !l.t !ll! !ll l!!!:llli7!!1B- !111!1LCORNER CUT, ECHELONSl NGLE ROW, PLAN F, S: BCORNER CUT, ECHELONSINGLE ROW, PLAN G, S 1.48FIGURE 2.- Generalized Blasting Patterns Showing B, S, b, and s (f).(Numbers indicate firing sequence.)
6De Diameter of the explosive in the borehole (in).B S Spacing, distance between two holes such that the spacing is alwaysBurden, distance from a charge measured perpendicularly to thenearest free face and in the direction that displacement willmost likely occur at the time of charge firing (ft).'measured perpendicular to its corresponding burden (ft).H Hole length (ft).J Subdrilling length, depth hole is drilled below the establishedquarry floor (ft).T Collar distance, the portion of the borehole not containingexplosive (ft).L Bench height (ft).bsDistance perpendicular to the original free face, measured betweentwo rows of holes (ft). See figure 2, plan A. Separation between adjacent holes in a row (ft).plan A.See figure 2,The terms b and s are used by quarry operators for convenience in describ-ing such patterns as plan A, a square grid. These terms should not be confused with burden and spacing. The word "explosives" is used as a collectiveterm for "blasting agents" and "explosives."EMPIRICAL FORMULAS THAT MAY BE APPLIED TODRILLING AND BLASTING PATTERN DESIGNAsh (}) has suggested five basic ratios for blasting design. Thestandard blasting ratios are for vertical boreholes for all types of benchblasting in 20 different rock types with hole depths from 5 to 260 ft, holediameters from 1-5/8 to 10-5/8 in, and for all grades of explosives. Althoughthe ratios can be used as first approximations in blasting design, modifications to the ratios will be pointed out where major geologic features influence blasting results.Ash's ratios will be shown as equations solving the unknown dimensions:whereB K9 De /12; Ks Burden ratio,s KsB;Ks Spacing ratio,HB;lS;1\tJ KJ B;(1)(2) Hole length ratio,(3)KJ Subdrilling ratio,(4)
7K1and Collardistance ratio.(5)D8 is expressed in inches, and all other dimensions are in feet.Calculationof Burden, B, From Equation 1To use a certain explosive type with diameter, D8 , the burden, B, can becalculated from equation 1. The following values for Ka are for rock with asolid density of around 2.7 gm/cc, a common value for limestone and dolomite.For calculating B, use:Ka 30 (average conditions--first approximation),K8 25 (for low-density explosives, such as AN-FO),andKs35 (for dense explosives, such as slurries and gelatin).If the rock has a density much different from 2.7 gm/cc, further adjustmentsof K8 can be made. A lower K8 value could be used for rocks of density muchgreater than 2.7, for example 3, and a higher K9 value could be used for rocksof density much les than 2.7, for example 2.4.Calculation of Spacing, S, From Equation 2Ks 1 8 - 2 for simultaneous initiation of holes in the same row.Staggered drill hole patterns should be preferred between rows within whichall charges are initiated simultaneously. Rock movement will generally beperpendicular to the original free face.According to Ash and others (!J), larger K8 values, for example Ks 3 - 5,could be used under favorable conditions for charges initiated together asopposed to the commonly accepted limit of 2. The charges would need to befired however at exactly the same time, otherwise spacing would have to bereduced because of the lack of enhanced stress effects. In addition, thelength of the charges must be sufficiently long.In regard to a minimum H/B condition, a recent studyand )showed:S (B H) l / 2 for 2B H 4B(6)S(7) 2B for 4B H.Ks 1.8 - 2 is satisfactory however although K8 could possibly be reducedfurther if H/B is much less than 3.According to ( ), individual blasting conditions will limit the value ofthe optimum spacing that might be used in any given
the interdependence of the drilling, blasting, and materials-handling operations. While the author was conducting his study (14), he noted many quarry operators were not cognizant of the work mentioned above. There was a lack of awareness of uncomplicated, first-approximation blast pattern design .
blast furnaces whose Inner Volume exceeds 5,000m3. Figure 2: Comparison of fuel rate and productivity between Blast furnaces of NSE's and others 1.2 Features of large blast furnace and proposed technology In general, stable operation is difficult for large blast furnace, productivity and gas utilization falls as inner volume becomes larger.
Blast injuries occur through multiple mechanisms.12 13 15 1njuries directly related to the initial blast wave are referred to as primary blast injuries. In addition to primary injuries, the blast wind that follows the overpressure wave can propel objects including shrapnel contained within the lED, causing secondary injury.
ducing agents for blast furnace is approved under the provisions of this law. 2. Use as a reducing agent in blast furnaces 2.1 Blast furnaces As shown in Fig. 1, iron ore and coke are loaded into the blast furnace from the top in alternate layers, and hot air from the tuyeres at the base of the furnace fed in to generate CO gas from the coke .
LLinear Patterns: Representing Linear Functionsinear Patterns: Representing Linear Functions 1. What patterns do you see in this train? Describe as What patterns do you see in this train? Describe as mmany patterns as you can find.any patterns as you can find. 1. Use these patterns to create the next two figures in Use these patterns to .
Assisted Airless Systems* Electrostatic Spray Systems, Flame Spray Systems and Plural Component Spray Systems* 1700 Abrasive Blast /Compressor-Surface Preparation Via Abrasive Blast removal, Using various Silica Free Abrasive media Sponge Blast and Media recovery systems. Compressor maintenance and Recognition of Abrasive Blast standards per SSPC.
Figure 1. The blast results using a non-filtered nr blast search for CLJ_B3418. The blast search can be set up slightly differently to prevent this problem from occurring. As noted in figure 2, we can set the search up to exclude, in this case, the taxid: 1485 (Clostridium). The taxid number stands for the NCBI Taxonomy ID number. By excluding the
1. Transport messages Channel Patterns 3. Route the message to Routing Patterns 2. Design messages Message Patterns the proper destination 4. Transform the message Transformation Patterns to the required format 5. Produce and consume Endpoint Patterns Application messages 6. Manage and Test the St Management Patterns System
What BLAST does (BLAST was developed by Stephen Altschul et al, 1990.It is the most-cited scientific paper ever.) BLAST looks for HSPs: HSP: "High-Scoring Pair" a grey region in the previous slide, i.e. a region of matching between your Query and a database entry (the Subject).HSPs usually don't have gaps in
