flyrock phenomena and area security

Safety Science 43 (2005) 739–750

www.elsevier.com/locate/ssci

Flyrock phenomena and area securityin blasting-related accidents

Vladislav Kecojevic *, Mark Radomsky

The College of Earth and Mineral Sciences, Mining Engineering Program, The Pennsylvania State University,

154 Hosler Building, University Park, PA 16802, USA

Received 10 November 2004; accepted 12 July 2005

Abstract

In both the mining and construction industries, blasting is the predominant method for fragmen-tation of consolidated mineral deposits. The blasting process, however, remains a potential source ofnumerous hazards to people and surrounding objects. This paper presents the results of the researchstudy on flyrock phenomena and blast area security related accidents in surface mining. The studyrevealed that a total of 45 fatal and 367 non-fatal accidents in coal, metal and non-metal surfacemines had occurred between 1978 and 1998 where the primary causes were the lack of blast areasecurity, flyrock, premature blast, and misfires. The lack of blast area security and flyrock accountedfor 281 (68.2%) accidents. Investigations of flyrock accidents have revealed one or more of the fol-lowing contributing factors: discontinuity in the geology and rock structure, improper blasthole lay-out and loading, insufficient burden, very high explosive concentration, and inadequate stemming.The study also shows that accidents due to lack of blast area security are caused by failure to useappropriate blasting shelter, failure to evacuate humans from the blast area, and inadequate guard-ing of the access roads leading to the blast area. The research results should have a positive impacton hazard awareness, prevention, and safe blasting practices in mining and construction industries.� 2005 Elsevier Ltd. All rights reserved.

Keywords: Blasting; Fragmentation; Mining; Flyrock and area security; Accidents; Prevention

0925-7535/$ - see front matter � 2005 Elsevier Ltd. All rights reserved.

doi:10.1016/j.ssci.2005.07.006

* Corresponding author. Tel.: +1 814 865 4288; fax: +1 814 865 3248.E-mail address: [email protected] (V. Kecojevic).

mailto:[email protected]

740 V. Kecojevic, M. Radomsky / Safety Science 43 (2005) 739–750

1. Introduction

The main purpose of blasting operations in surface mining is the rock fragmentation,and is considered to be essential to the success of mining operations. This process providesappropriate material granulation that will be suitable for excavation and transportation.According to the US Geological Survey (2000), the US coal, metal and non-metal surfacemining industry uses almost 1.8 billion kilograms of explosives annually. Between 1989and 1999, surface coal mines have used 16.2 billion kilograms and 3.3 billion kilogramshave been used in non-metal mines and quarries (Kramer, 2000).The blasting process, however, remains a potential source of numerous hazards. Even

though the mining industry has improved its blasting safety, there are still reports indicat-ing blasting-related accidents involving both people and various structures. Investigationscarried out by the Mine Safety and Health Administration (MSHA, 1994; MSHA,1999a,b) provide clear evidence regarding the severity of these accidents. Figs. 1 and 2show the fatal and non-fatal blasting accidents from 1978 to 1998 for coal, metal andnon-metal surface mining (Verakis and Lobb, 2001). A total of 45 fatalities occurred

0

5

10

15

20

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

Year

Nu

mb

er o

f ac

cid

ents

Fatal Nonfatal

Fig. 1. Number of fatal and non-fatal blasting accidents in coal surface mining.

0

5

10

15

20

25

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

Year

Nu

mb

er o

f ac

cid

ents

Fatal Nonfatal

Fig. 2. Number of fatal and non-fatal blasting accidents in metal and non-metal surface mining.

Miscellaneous4.10%Misfires

5.64%

Premature blast 16.92%

Flyrock27.69%

Blast area security45.64%

Fig. 3. Blasting accident causes in coal surface mining (1978–2001).

V. Kecojevic, M. Radomsky / Safety Science 43 (2005) 739–750 741

during the entire period, an average of 2.14 fatalities per year. Coal mining accounted for44.68% of the fatalities, while metal and non-metal operations for 55.32%. For the sameperiod, a total of 367 non-fatal injuries have occurred, an average of 17.47 per year.Further historical data summarized by Verakis and Lobb (2003) shows that for the per-

iod of 1978–2001, a total of 195 blasting accidents occurred in US surface coal mine oper-ations. Of the 195 accidents, 89 accidents (45.64%) were directly attributed to lack of blastarea security, 54 accidents (27.69%) to flyrock, 33 (16.92%) to premature blast, and 11(5.64%) to misfires (Fig. 3).Since flyrock and a lack of blast area security constitute the majority of all blasting-

related accidents, the cause and control of these hazards and activities are discussed.

2. Flyrock phenomena

Flyrock is defined as the rock propelled beyond the blast area by the force of an explo-sion (IME, 1997). The uncontrolled material fragments generated by the effects of a blastare one of the prime causes in blasting-related accidents. When these rock fragments arethrown beyond the allowable limits they result in human injuries, fatalities and structuredamages. Fig. 4 shows flyrock occurrences during the blasting process.Previous experimental and theoretical work about flyrock phenomena has been per-

formed by Langefors and Kishlstrom (1963), Ladegaard-Pedersen and Persson (1973),Lundborg (1974, 1981), Holmeberg and Persson (1976), and Roth (1979). Ladegaard-Pederson and Persson (1973) have performed experiments in Plexiglas (polymethylmetha-crylate—PMMA). Their drilling experiment involved a single hole in a block of PMMA,and variation of the explosive charges by a factor approaching 2. They concluded that asthe charge increases, the fragmentation and the velocity of the broken material increases aswell. They also found that the gaseous venting from the blast penetrated the fractureplanes perpendicular to the hole axis and broke the material up and propelled them. Theyalso conducted a series of bench blast tests with a single hole in rock boulders. The drill-hole diameter was 25 mm. After each single hole blast, the distance from the hole and theangles of the flyrock were determined.Holmeberg and Persson (1976) studied flyrock in field experiments with high-speed

cameras. They concluded that most of the collar flyrock are thrown in a direction follow-ing the drillhole axis. Their experiments also confirmed that the scatter of the angle ofthrow increases as the unloaded hole length decreases.

Fig. 4. Flyrock generation in blasting process (Cameron et al., 2003).


The theory for predicting flyrock from blasting operations in hard rock such as granitehas been developed by Lundborg (1974). The charge hole diameter has been established asd = k/qv, where k is a constant. To determine the constant k, measurements of the /qvwere made for different d values. By doing so, the relation 10d ¼ /qv

2600was obtained where

q is the density of the rock in kg/m3 (2600 kg/m3 is the average density of granite), / is thefragment size diameter in meters, and v is the fragment velocity in m/s. To investigate thevalidity of this equation, and to determine the factor of proportionality, several blasts werephotographed and the flyrock velocities measured. In a number of blasts, the maximumdistance of throw and the diameter of each flyrock fragments were also measured. By usingthe previous equation, the maximum throw was calculated as Rmax = 260d

2/3, where R is inmeters.Additional studies on flyrock phenomena can be found in Persson et al. (1984), Baj-

payee et al. (2000), Fletcher and D�Andrea (1986), Rehak et al. (2001), Shea and Clark(1998), and Siskind and Kopp (1995). Generally, flyrock is caused by a mismatch of theexplosive energy with the strength of the rock mass surrounding the explosive charge.Investigations of flyrock accidents have revealed one or more of the following contributingfactors: (i) discontinuity in the geology and rock structure, (ii) improper blasthole layoutand loading, (iii) insufficient burden, (iv) very high explosive concentration, and (v) inad-equate stemming.

2.1. Geology and rock structure

The rock structure and rock properties may vary considerably from a location to loca-tion even within the same blast area. Discontinuity in the geology and rock structurecauses a mismatch between the explosive energy and the resistance of the rock. Existenceof fissures, joints, weaknesses, and voids are likely to assist in the creation of flyrock. Thecompressive strength, abrasiveness and the rock density also play a very important role inthe blasting process, as does the spatial distribution of rock properties. Base information(e.g. consolidation, voids, etc.) regarding the rock structure and properties of the material


to be blasted can be routinely obtained from drill hole logs, and must be considered priorto hole loading. A much more in-depth analysis of geologic characteristics can be achievedthrough modeling. Realistic representation of geological domain requires a form of a spa-tially referenced database that provides means for modeling a 3-D body from all geolog-ical and geophysical data. Depending upon the rock type, data can be analyzed andmodeled using:

(a) Stratigraphic modeling, where a set of grid surfaces and subsequent intervals repre-sent a sedimentary deposit; or

(b) Discrete fracture network (DFN) approach and incorporates deterministic, condi-tioned, and stochastic features; or

(c) Block modeling where each block consists of unique rock strata propertyinformation.

As a result, a 3-D model can be generated providing information and spatial visualiza-tion of the rock structure as shown in Figs. 5–7. Spatial analysis offers a number of

Fig. 5. Stratigraphic model of sedimentary deposit (Mincom, 2004).

Fig. 6. Block model of rock properties (Surpac, 2004).

Fig. 7. Discrete fracture network model (Golder Associates, 2004).


advantages. Rock properties data can be obtained or predicted at each location, and canbe quickly investigated and visualized in 3-D. This would allow quick response to changesin rock conditions by providing an opportunity for early identification of possible prob-lems. Secondly, it is very important that the surface rock is inspected for faults and planesbefore blasthole charging. Previous excavations can give significant information about therock structure. Best-in-class safety performance can be achieved when regular geologichazard or exception mapping occurs by trained foremen and/or mine geologists. Incorpo-rating geologic variability can be routine by including exception mapping into the periodicstripping plan. Most surface mine operations plan pit sequencing and stripping on aweekly to a monthly basis.

2.2. Blast hole pattern

Inaccuracies in the design of blasting patterns, including incorrect blasthole angle cancause large deviations from the planned pattern resulting with flyrock occurrence. Com-monly, the graphical design of drilling and blasting patterns is performed by using 2-Dcomputer aided design (CAD) tools, or is generally determined by drill operator experi-ence. However, 2-D design techniques do not consider spatial characteristics of rock prop-erties and usually use the average value of a parameter that is of interest. An engineer�sability to analyze interactions among rock properties, geology, and pattern design couldbe enhanced considerably using 3-D graphics. Fig. 8 shows an example of pattern designusing state-of-the-art technology such as MineScape (Mincom, 2004). The entire drillingand blasting domain can be visualized from different angles, thus, forewarning about pos-sible trouble spots before drilling. More detailed description on 3-D design of drilling andblasting patterns can be found in Kecojevic et al. (2003), Kecojevic and Wilkinson (2003),and Wilkinson and Kecojevic (2004).

Fig. 8. 3-D representation of blasting pattern.


2.3. Burden

Insufficient burden is one of the primary causes of flyrock (Fig. 9). Too short a distanceto the bench slope wastes energy, while too great a burden distance causes improper frac-turing of the rock, creating oversize boulders. Due to irregularity of bench slopes, energygenerated during blasting pose the hazard at the weakest point of the bench. Furthermore,any deviation during the drilling process can increase or reduce the burden. A common

Fig. 9. Typical blasting hole in surface mining (Fernberg, 2003).

Fig. 10. A Global Positioning System (GPS) installed on the drill system (Modular Mining System, 2002).


problem in small mining operations is the lack of knowledge and accurate technology toidentify and recognize the specific anomaly or weakness in the rock structure that leads tothe subsequent flyrock problem. The blaster is aware that flyrock can occur if the holedeviates from the intended direction and goes to close to the free face.Until recently, a convenient means of gathering drilling records were not available.

Wireless technology applied at the drilling rig may help to resolve this problem. Drillingmachines can be instrumented with the variety of sensors, from which data can be digitizedand transmitted to any location for analyses. A global positioning system (GPS) installedon the drill system can provide the precise locations of boreholes drilled (Modular MiningSystem, 2002). Each borehole can be surveyed to provide an as-built record of the drillingaccuracy accomplished at each location (Fig. 10). The operator also can provide the on-the-spot assessment of situations that result in drill downtime, or unusual performanceof the system at the given location. In such an arrangement, the machine location, changesin geology, unusual rock strata features and machine defects could all be documented atthe same setting.The Aquila Mining Systems (2004) has developed a production monitoring system, a

material recognition system, and a guidance system for vertical and inclined drilling.The production monitoring system provides the operator with immediate informationon drilling productivity and performance, while the material recognition system isequipped with vibration sensors and pattern recognition software to determine hole geo-logy while drilling. Guidance systems for vertical and inclined drilling enable the operatorto position the blast hole with centimeter accuracy.

2.4. Blasthole loading

Blasthole overloading is one of the frequent causes of flyrock occurrence. Such over-loading generates excessive release of energy. It appears due to the loss of powder in fis-sures, joints, voids, and cracks. In order to prevent hole overloading, it is necessary toload holes as designed using the correct charge weight. Additionally, a blast ratio should


be ensured sufficiently high to eliminate the possibility of excessive charging, and holeshave to be monitored to check the rise of the powder.

2.5. Stemming

Stemming material provides confinement and prevents the escape of high-pressure gasesfrom the blasting holes. This material must be free from rocks and properly tamped. Inad-equate stemming results in stemming ejections from the holes resulting with flyrock. Ingeneral, the stemming length should be not less than 25 times the blast hole diameter(Sheridan, 2002). Konya and Walter (1990) recommend a steaming length of 0.7 timesthe burden.

3. Blast area security

The US Code of Federal Regulations—CFR, Title 30 defines �Blast Area� as the area inwhich concussion (shock wave), flying material, or gases from an explosion may cause in-jury to persons. Furthermore, the CFR states that the blast area shall be determined byconsidering geology or material to be blasted, blasting patterns, blasting experience ofthe mine personnel, delay systems, type and amount of explosive material, and type andamount of stemming.During the last two decades, lack of securing blast areas caused 45.64% of the fatal and

non-fatal accidents in coal surface mining due to failure to use appropriate blasting shel-ter, failure to evacuate blast area from humans, and inadequate guarding of the accessroads leading to the blast area. Failure to evacuate humans from blast areas is complicatedby the increase in accessibility to rough terrain brought on by the substantial increase inuse of all terrain vehicles (ATV�s). Areas inspected to be all-clear can be infiltrated by non-mining personnel on ATV�s within seconds. The issue of blast area security can be success-fully addressed by providing appropriate training and education of personnel involved inblasting operations to apply the best safety practices, as well as state and government reg-ulations. Furthermore, the blast area must be inspected to determine distances to nearbystructures, roads, public places, and due consideration must be taken in determining thedegree of protection necessary, including the use of line-of-sight inspection methods toguard against ATV�s. It is of primary importance to clear all employees from the blastarea, guards should be posted at the entrance to all access roads leading to the blast area,and the blaster should communicate to the foreman about the impending blast. The blas-ter must go outside the blast area or stay inside a blasting shelter, and after receiving thefeedback from the foreman and guards, blast signal needs to be sounded. A detailed studyon safeguarding blast-affected areas is given by D�Andrea and Bennett (1984).Furthermore, blasting regulations (30 CFR Part 77.1303) require that ample warning

shall be given before blasts are fired, and all persons shall be cleared and removed fromthe blast area unless suitable blasting shelters are provided to protect persons endangeredby concussion or flyrock from blasting.

4. Safety evaluations

The administration of industrial safety rests on the foundation that accident investi-gation results in the identification of cause followed by the appropriate response or


correction in procedure. This approach can be referred as reactive safety, since the safetyresponse mechanism occurs after an accident. The proactive safety response mechanismoccurs when corrective action is taken after a non-event called a near-miss. A benchmarksafety study done in 1969 involving over 3 billion man-hours revealed for every serious ordisabling or serious injury, 10 minor injuries occur, 30 property damage events occur, and600 incidents occur with no visible injury or damage (Bird, 1974). The 1-10-30-600relationships indicate the essential value of proactive safety and the prevention of acci-dents depends on addressing the near-misses.Dyno Nobel Corporation, like other large explosive manufacturers, provides product

delivery to the minesite, and in fact into the very drill hole in mining operations. Exposureof an explosive�s manufacturer�s employees is therefore equal to miners. Dyno NobelNorth America implemented a proactive safety program of which one the main elementswas a near-miss reporting and evaluation procedure for their employees. The results havebeen excellent. For example, for the period from 1995 to 1998, lost time injury frequencyrate decreased from 4.44 to 1.11, and lost time injury severity rate decreased from 95 to 29.The approach of reporting near-misses affected safety performance in a large magnitude.

5. Education and training

Effectively training the workforce in blasting hazard recognition and avoidance, and thesafe use of explosives is an essential activity in reducing blasting incidents. In the UnitedStates, the use of explosives in mining is regulated at both the Federal and states� level. Thefederal government and individual state governments maintain and enforce health andsafety, and training standards to help minimize blasting mishaps that endanger life andproperty. While each government entity works toward the same goal, the federal govern-ment and state governments assume somewhat different approaches to achieving the goal.Under federal training regulations contained in Title 30, CFR, Parts 48 and 46, (USDepartment of Labor, 2002) mining companies are required to train miners in the hazardsrelated to explosives and safe blasting requirements through training curriculum contentpresented in either what is known as comprehensive training courses, i.e., new miner, an-nual refresher, newly-hired experienced, new task training, or hazard training (typicallyprovided for contactors working on mine sites, or occasional visitors and service workers).It would be accurate to say that if the mine uses explosives, the miner or contractor will beinstructed at a minimum in blasting hazards and avoidance, and if the miner is assigned toa blasting crew, in the safe use of explosives. This instruction on the safe use of explosiveswould be provided in a task training course or a task training session within a new minertraining course. The federal training regulations, if fully complied with, ensure that allminers and visitors are, at a minimum, trained in basic blast hazard awareness.State level involvement in achieving the goal of safe blasting activities typically includes

the establishment and implementation of a program of blasters� training, examination, andcertification. The general purposes of these programs are to ensure that ‘‘blasts’’ are de-signed, supervised, and executed by trained and competent personnel (Alabama SurfaceMining Commission Administrative Code, 2004). As an example of the training curricu-lum content, Pennsylvania�s programs includes, but is not limited to, discussion andinstruction on regulations, scaled distances, blast design, blasting materials, initiation sys-tems, and record-keeping (Bureau of Mining and Reclamation, 2003). While the particu-lars of the programs differ by state, applicants to the program must pass a competency


examination before being awarded a blaster�s license. The licensed blaster becomes the‘‘blaster-in-charge’’ for each blast. Such licensing programs attempt to maximize blastingaccident prevention by ensuring that the blast be designed and executed in strict accor-dance with the statutory rules, and that adequate supervision, monitoring, and controlof all blasting activities be administered by a certified person.

6. Conclusion

The historical trend over the 23-year period is a general decrease in the number of inju-ries and fatalities from blasting accidents for coal, metal and non-metal operations. Eventhough blasting accidents for all types of mining operations have declined, they continueto occur and cause fatalities and injuries. Mining personnel continue to suffer fatal anddisabling injuries from blasting accidents. An analysis performed shows that the lack ofblast area security and flyrock accounted for 281 (68.2%) accidents during the analyzedperiod.A major challenge facing users of blasting techniques is how to apply the state-of-the-

art technology to assist them in evaluation of the potential to cause harm to workers, andto develop effective strategies for control and to minimize occupational health hazardsassociated with blasting. Training and education of personnel involved in blasting opera-tions play a critical role in preventing fatalities and injuries, and should be focused on:codes and standards, workplace responsibility, assessing and developing accident preven-tion strategies, developing workplace safety procedures, implementing work practices thatmeet specified legislation and standards, identifying strategies for monitoring and updat-ing safety and health information, effective occupational health and safety communica-tions, and improving occupational health and safety performance.

References

Alabama Surface Mining Commission Administrative Code, 2004. Chapter 880-X-Training Examination, andCertification of Blasters� Training, Examination, and Certification Program for Blasters. Alabama SurfaceMining Commission.

Aquila Mining Systems, 2004. Aquila Mining Systems Products: Available from: <http://www.aquilamsl.com/frameset2.html>, Montreal.

Bajpayee, T.S., Rehak, T.R., Mowrey, G.L., Ingram, D.K., 2000. A summary of fatal accidents due to flyrockand lack of blast area security in surface mining, 1989–1999. Proceedings of the 27th Annual Conference onExplosives and Blasting Technique, vol. I. International Society of Explosives Engineers, Cleveland, USA.

Bird, F., 1974. Management Guide to Loss Control. Institute Press, Loganville, p. 17.Bureau of Mining and Reclamation, 2003. Surface Blaster Training & Examination. PA Department ofEnvironmental Protection, Harrisburg.

Cameron, A., Forsyth, B., Kleine, T., 2003. Blast Design and Assessment for Surface and Underground Mining.Golder Associates, Reno, p. 46.

D�Andrea, D.V., Bennett, J., 1984. Safeguarding of blast-affected areas. In: Proceedings of the 10th AnnualConference on Explosives and Blasting Technique. International Society of Explosives Engineers, Cleveland,pp. 100–121.

Fernberg, H., 2003. Principles of Rock Blasting. Surface Drilling, first ed. Atlas Copco, Sweden, pp. 6–8.Fletcher, L.R., D�Andrea, D.V., 1986. Control of flyrock in blasting. In: Proceedings of the 12th AnnualConference on Explosives and Blasting Technique. International Society of Explosives Engineers, Cleveland,pp. 167–177.

Golder Associates, 2004. Technical Bulletins, www.fracman.com.

http://www.aquilamsl.com/frameset2.html

http://www.aquilamsl.com/frameset2.html

http://www.fracman.com


Holmeberg, R., Persson, G., 1976. The effect of stemming on the distance of throw of flyrock in connection withhole diameters. Swedish Detonic Research Foundation, Report DS 1976:1, Stockholm.

Institute of Makers of Explosives (IME), 1997. Glossary of commercial explosives industry terms. Safetypublication, No. 12, Institute of Makers of Explosives, Washington, DC, p. 16.

Kecojevic, V., Mrugala, M., Wilkinson, W., 2003. 3-D visual drill and blast design. International Journal of RockFragmentation and Blasting 7 (3), 167–179.

Kecojevic, V., Wilkinson, W., 2003. Computer-aided design and high-precision systems in drilling and blasting.The Journal of Explosives Engineering, ISEE 20 (4), 12–16.

Konya, C.J., Walter, E.J., 1990. Surface Blast Design. Prentice Hall Inc., NJ, p. 303.Kramer, D.A., 2000. Mineral industry surveys. Explosives 1999 Annual Review, Reston.Ladegaard-Pedersen, A., Persson, A., 1973. Flyrock in Blasting II, Experimental Investigation, Swedish DetonicResearch Foundation, Report DS 1973: 13, Stockholm.

Langefors, U., Kishlstrom, B., 1963. The Modern Technique of Rock Blasting. John Wiley & Sons, New York,NY.

Lundborg, N., 1974. The hazards of flyrock in rock blasting. Swedish Detonic Research Foundation, Reports DS1974:12, Stockholm.

Lundborg, N., 1981. Risk for flyrock when blasting. Swedish Council for Building Research, BFR ReportR29:1981, Stockholm.

Mincom: MineScape Products, 2004. Available from: <http://www.mincom.com/products/minescape>.Modular Mining System, 2002. ProVisionTM Drill Technical Bulletin. Available from: <www.mmsi.com>.MSHA, 1994. Accident investigation report: surface nonmetal mine, fatal explosives and breaking agent�saccident. Alton Stone Company, Inc., IL.

MSHA, 1999. Report of investigation: fatal explosives accident. Surface nonmetal mine. Compass Quarries Inc.,Paradise, Lancaster County, PA.

MSHA, 1999. Accident investigation report: surface coal mine, fatal explosives accident. Appalachian MiningServices, Big Creek Mining, Inc., Mine no. 2, KY.

Persson, P., Holmberg, R., Lee, J., 1984. Rock Blasting and Explosives Engineering. CRC Press, New York, NY,p. 565.

Rehak, T.R., Bajpayee, T.S., Mowrey, G.L., Ingram, D.K., 2001. Flyrock issues in blasting. Proceedings of the27th Annual Conference on Explosives and Blasting Technique, vol. I. International Society of ExplosivesEngineers, Cleveland, pp. 165–175.

Roth, J., 1979. A model for the determination of flyrock range as a function of shot conditions. US Bureau ofMines contract J0387242. Management Science Associates, Los Altos.

Shea, C.W., Clark, D., 1998. Avoiding tragedy: lessons to be learned from a flyrock fatality. Coal Age 103 (2), 51–54.

Sheridan, R.A., 2002. Precautions against flyrock. Explosives Information Bulletin. Explosives Inspectorate,Safety and Health Administration, Queensland Government, p. 3.

Siskind, D.E., Kopp, J.W., 1995. Blasting accidents in mines: a 16 year summary. In: Proceedings of the 21stAnnual Conference on Explosives and Blasting Technique. International Society of Explosives Engineers,Cleveland, pp. 224–239.

Surpac, 2004. Technical Bulletins. Available from: <www.surpac.com>.USGS, 2000. Mineral industry surveys, explosives. 1999 Annual Review, US Geological Survey, Reston, VA.US Department of Labor, 2002. Title 30, Code of Federal Regulations. US Government Printing Office,Washington, DC.

Verakis, H.C., Lobb, T.E., 2001. Blasting accidents in surface mines, a two decade summary. Proceedings of the27th Annual Conference on Explosives and Blasting Technique, vol. I. International Society of ExplosiveEngineers, Cleveland, pp. 145–152.

Verakis, H.C., Lobb, T.E., 2003. An analysis of surface coal mine blasting accidents. 2003 SME Annual Meeting,Society for Mining, Metallurgy, and Exploration, Littleton, Preprint # 03-081.

Wilkinson, W., Kecojevic, V., 2004. Elements of drill and blast design and 3D visualization in surface coal mines.2004 SME Annual Meeting, Society for Mining, Metallurgy, and Exploration, Littleton, Preprint # 04-19.

http://www.mincom.com/products/minescape

http://www.mmsi.com

http://www.surpac.com

flyrock phenomena and area security

Documents