Search Documents

By Richard J. Mainiero, T S. Bajpayee

The Bureau of Mines, U.S. Department of the Interior, has developed test procedures and criteria for evaluating explosive reactivity of explosive contaminated solid waste substances generated by U.S. Army Ammunition Plants. These substances are produced as explosive-contaminated sludge from waste water treatment plants, residues from the burning of munitions and explosives on open ground, and residues from deactivation furnaces. The characterization of explosive reactivity is a prerequisite for disposal of such waste materials, which may be contaminated with primary explosives, propellants, or pyrotechnic materials. The Bureau has proposed two tests for this purpose. These tests were developed to evaluate the explosive reactivity as defined in Title 40, Code of Federal Regulations, Part 261.23(a)(6) and (7). These are Bureau of Mines Gap and Bureau of Mines Internal Ignition tests, which determine the sensitivity to shock and thermal stimuli, respectively. This paper also includes gap and internal ignition reference data for typical blasting agents, high explosives, propellants, and marginally reactive substances. These reference data were used to establish test criteria. The Bureau has evaluated over 400 samples of contaminated soil, sludge, and burning residues using these two test methods.

Jan 1, 1988

By Karl E. Burger

Recently an experiment was completed at the Golden Sunlight Mine, a property owned by Placer Dome Inc. of Vancouver, British Columbia, to measure the Body Waves entering their highwall created by blasting. The purpose of the study was to assess the damaging effects of blasting on the highwall, in order to further slope stability. Stress and Strain experienced in the earth that is created as a result of blasting can be determined by knowing several important pieces of information. These include the compressional and shear wave particle velocities initiated by blasting, the Body Wave travel velocities in both the shear and longitudinal direction, and the densities of the rock in question. A series of equations based on wave theory can then be used to determine the stress and strain affecting the highwalls. The Blasting Engineer can then use this information to design blasts that create peak particle velocities less than levels that maintain the integrity of the highwalls. This paper first discusses the experiment used to measure the Body Wave velocities. It then traces through the subsequent calculations necessary to generate the information needed by the Blasting Engineers, the Mining Engineers, the Geological Engineers, and the Geophysicists to design blasts and develop open pit plans to alleviate unstable highwall conditions.

Jan 1, 1989

By Adrian Moore, Alan Richards

Time window techniques that limit the explosive charge mass being fired within a specified time window (commonly 8 milliseconds (ms)) have been used for many years and are widely accepted by explosives engineers. The 8 ms time window may be relevant for controlling ground vibration for small blasts at close quarters in a high frequency vibration environment. For controlling ground vibration from blasts in a low frequency vibration environment an 8 ms separation between blastholes is arbitrary and meaningless. The 8 ms time window was never intended as a means of controlling airblast. The use of time window techniques will, in many instances, result in airblast and ground vibration levels that are substantially greater than planned, with unfortunate outcomes. The uses of time windows that are inappropriate have been well explained in previous papers. This paper gives further examples of blast designs that satisfied time window considerations but have resulted in substantially greater airblast and ground vibration levels in certain directions, due to wavefront reinforcement or the combined effect of drilling pattern and delay sequence. Techniques that identify wavefront reinforcement, due to the combined effect of drilling pattern and delay sequence, can assist explosives engineers to avoid blast vibration problems that result from inappropriate time window techniques.

Jan 1, 2002

By Michael M. Jackson

"The mining industry has for some time compared explosive energy requirements to theresults obtained using ANFO. Drill patterns, powder factors, and explosive bulk strengthshave all been developed based on the detonation characteristics and blasting resultsexhibited by ANFO. However, there are some mining applications where the use of ANFOcan cause over_blasting if loaded to acceptable collar heights or surface breakage problemsif collar heights are reduced. A specialized, low strength, low density water gel explosivehas been developed that has loading densities in the range of 0.4 to 0.7 g/cc. The uniquecharacteristics of the low density water gel explosive is that the explosive can beformulated with a range of available bulk strengths while maintaining excellent detonationsensitivity for use in applications involving ore/waste control, restricted blast patterns,small bench heights, etc. The"

Jan 1, 1993

By M S. Sandhu

Singrauli area of Madhya Pradesh in India has been developed as the power capital expected to produce around 11000 MW in near future requiring 65 million tonnes of Coal per annum. Thermal power plants were installed considering the vicinity of coal reserves which are minable by open cast mining methods. Crisis of oil in seventies further expedited the process of planning big open-cast projects in the area varying from capacity of 3 million tonnes of coal to 14 million tonnes per annum. A separate company - Northern Coalfields Ltd. was formed to ensure meeting the rising demand of coal required for energy production. Northern Coalfields at present is producing 35 million tonnes of coal and will reach the capacity of peak demand of 65 million tonnes by the turn of the century.

Jan 1, 1998

By Jim Daley

SEE is a dynamic organization composed of people from all facets of the explosives industry who are truly interested in the advancement of that industry. I had been a miner at the Homestake Gold Mine in Lead, SD for 12 years when I decided to obtain a mining engineering degree. The mental and economic consequences of that decision were more severe than we had imagined. The joint scholarship program of the Northern Plains and Black Hills Chapters of SEE provides assistance to several college students each year. I was fortunate enough to receive scholarships from this program twice and this assistance helped me and my family with both monetary and psychological support during times of need so that we could stay focused on the goal of obtaining a degree.

Jan 1, 1995

By Ron J. Elliott, David G. Otto

This project involved deep blast densification of recent volcanic avalanche debris deposits consisting of a 43 meter thickness of loose clean to slightly silty sand, gravel, cobbles and boulders deposited as a result of the 1980 eruption of Mt. St. Helens, Washington, U.S.A. This project was carried out to enhance the resistance to liquefaction or dynamic settlement of soil deposits under the bridge abutments for construction of the 59.4 meter long South Coldwater Creek Bridge. As this bridge is located close to the Mt. St. Helens fault, it will in all likelihood be subject to earthquakes in the order of 6.5 with expected accelerations of 0.55g. Without soil densification, the bridge would suffer severe structural damage in the event of a significant earthquake.

Jan 1, 1994

By Herve Duplaine, Charles H. Dowding

Calculation of response spectra for blast induced vibrations is necessary to fully understand and in some instances comply with frequency or distance related safe blasting criteria. Fortunately, micro-computer systems costing less than $5000 (such as that described herein) can be programmed to calculate response spectra. This system will calculate response spectra from paper as well as FM tape records. It both digitizes (prepares the record for computer calculation) as well as calculates. Programs for the calculation have been written in BASIC, an easy to understand language used with word processors. In addition to describing the equipment and operation of the micro computer the paper will discuss the process of and rules for digitization, use of the computer for record production and will present a simple physical model for understanding dynamic structural response.

Jan 1, 1984

By J J. Mullay, G W. Anderson, C J. McFinley, J F. VanNorman, C J. Kefer

Previous work has shown that testing of precompression effects conducted on a small scale under simulated field conditions in actual rock provides a reasonable model for the evaluation of explosives and initiators under the adverse conditions encountered in production blasting. Using this methodology can result in greater understanding of the phenomena as well as the ability to predict performance. This effort has been extended to evaluate various parameters not previously studied in a controlled fashion. The present paper describes the use of this technique to study the effects of delay timing on precompression effects. Intervals from 25 to 150 milliseconds are included in the study. Both VOD measurements and damage estimates are utilized in the evaluation. The results demonstrate that timing delay between holes is quite important in determining the overall effectiveness of a blasting program.

Jan 1, 1994

By Bryan Papillon, Karl Christopherson

In order to improve vibrations from quarry blasting, a new technique and timing pattern was established and applied to the particular geology. By shooting a single representative borehole one full second ahead of the production blast, a signature waveform can be isolated and analyzed. Multiple productionsignature blasts were performed. Encroaching residences require quarries to adjust their blasting techniques to reduce vibrations and raise frequencies. A signature hole inherently poses problems to quarries. Blasting one single hole from a production bench poses safety issues to wall stability; vibration issues to close neighbors; and budget issues to the quarry operator. Results showed that the new timing pattern reduced vibrations through timing optimization without a loss in quarry production. Therefore, this technique of vibration analysis employing a production-signature hole is successful in creating a timing pattern that meets the quarry’s goals.

Jan 1, 2008

By R Mancini, G Borla

This paper analyses the first results of a part of an EEC research project ("Blasting control for underground mining"). This research that involves three universities (Paris, Torino and Leoben) has been carried out at the Eisenerz test mine in Austria. In the experimental campaign here reviewed, parallel holes rounds have been fired "decomposed", which means with enough delay between the explosions of the successive blastholes groups to allow for a separate evaluation of their effects on the rock. The seismic effects have been recorded by geophones placed at small distance from the blast, the aim being to find out correlations between the features of the seismogram and the good or poor performance of the single blastholes, or of the groups pertaining to the same delay. Indeed, the seismogram is the only safe and cheaply obtainable description of what happens during the blast. The seismogram should be transformed in a diagnostic tool in the round 'calibration' stage, and in a routine control device during excavation.

Jan 1, 1995

By H Leonard Mangum, Victor C. Bryan, Dan McCutchen

Recently there has been an unprecedented marketing effort to promote the advantages of various non-electric initiation systems. This activity has probably been influenced by a major manufacturer's decision to discontinue electric detonator production. Subsequently, distributors of explosive materials, rather than introducing new electric detonator brands, are emphasizing the use of existing non-electric systems. In many cases, such methods fill the need of explosive users in the quarry industry. However, the use of any initiation system should be based on performance, rather than the bent of the market or convenience to the supplier. This analysis is an evaluation of the performance of non-electric systems with emphasis on double trunk line and loop (redundant), as compared to precise electric detonators in use by Martin Marietta. Redundant non-electric detonators, even though more costly, offer the most reliable method of non-electric initiation. However, state-of-the-art precise electric detonators give the best overall performance, except in an environment involving extraneous electricity.

Jan 1, 1990

By Bradley C. Paul

Similar rock formations exhibit great variability in resistance to fragmentation during crater blasting. This observation was made during an attempt to calibrate the Kuz-Ram blast fragmentation model for crater blast geometries used in a modified in situ mining method for copper. The KuzRam equation is used to predict the fragment size distribution from blasting and includes a term called the "rock factor" to account for the fragmentation characteristics of the material. A data base of field scale crater shots in oil shale was available to supplement more limited data on copper ores. First, the blast geometry terms of the Kuz-Ram formula were modified to fit field data with various crater blast geometries. Rock factors were chosen to center the predicted curve on the curve representing observed fragmentation. Next, five possible sources of variability in rock factor were investigated: the grade of the oil shale, the aspect ratio of the charge, the type of explosive, the charge depth, and the rock itself.

Jan 1, 1989

Several surface coal mining operations in North America are attempting to adapt microprocessor-based monitoring equipment as well as programmable logic controllers onto rotary blasthole drills, towards improving overall drill and blast productivity. These Monitoring While Drilling (MUD) systems permit the recording and processing of important drilling parameters such as rotary speed and torque, instantaneous penetration rate and weight on the bit, and enable the operator ultimately to optimize drill and bit performance. MWD systems on production drills in surface coal mines offer the potential to define mine bench geology in detail and in advance of explosives loading. Recent advance s in explosives and initiation technology will require such a detailed knowledge of ground conditions in order to be fully exploited. Additionally, the logic developed from drill monitoring technology will eventually enable full drill automation through feedback and control, once a more complete understanding of the influences of rock mass characteristics on machine performance is achieved.

Jan 1, 1988

By C M. Deosthale, V N. Pangal, M N. Rao

New Mangalore Port is the most important port in Karnataka State, on the west coast of India on Arabian Sea. It handles export of iron ore, granite, coffee, spices etc and imports of crude oil, fertilizers etc. Since 1991, after economic liberalisation by the Government of India, the exports and imports at this port got a boost. Hence the Port Trust felt the need to increase the draught by about 3 to 5 meters for access to bigger ships. In response to a global tender in 1995, the Dutch Dredging Company got the contract to remove 30,000 cu.m of hard granite bed rock, covering 28,000 sq.mtr. area for the Turning Circle and oil Jetty. The operations of drilling, blasting and dredging were to be carried out to deepen the area to about 15 m draught without affecting the normal trade at the Port. This was a time bound contract to avoid interruption by severe Monsoon rains.

Jan 1, 1999

By M Siefert, P Moser, T Oberndorfer

"The EC-project ""Blasting Control"" with partners from France, Austria, Italy and Greece dealt with the development of a diagnosis system, which enables blasting experts to investigate in detail on probable reasons of poor blasting results in underground drifting. The system incorporates monitoring of geometric, explosive, vibration and granulometry data. All data are compiled in a database and are provided for direct retrievement by demand of the experts in a graphical environment. This paper focuses on the advantages of such graphical system for both research tasks and applications in real testing situations. It describes the procedure of monitoring and presents a selection of graphical outputs generated during data processing immediately after blasting. Benefits of detailed monitoring in respect of detecting sources of errors are explicated by a actual example of a test series in a mine. The paper will conclude with an outlook onto the scientificresearch work which is planned to be based on the results of hitherto investigations."

Jan 1, 1996

By D O. Doehring, W A. Charlie, W A. Lewis

The detonation of explosive charges releases large quantities of energy that can produce rock and soil deformations far from the detonation point Extensive data are available on blasting in general and on the performance of certain structures subjected to blast vibrations. However, only limited information is available on the performance of earthfill dams and other hydraulic structures subjected to blasting. The limited data indicate that, whatever the cause, one or several cycles of repeated strains in earthfill dams may cause residual porewater pressure increases. Limiting the peak particle velocity to less than 2.5 cm/s for operating dams constructed of or having foundations consisting of saturated, loose sands or silts and to less than 5 cm/s for other earthfill dams, should keep strains below the threshold strains required for residual porewater pressure increases to occur. Porewater pressures should be monitored throughout a blasting operation, and they should be allowed to dissipate, if necessary, before subsequent charges are detonated.

Jan 1, 1987

By Thomas E. Ricketts

An important part of underground mine planning and operations involves the reclamation of working areas after blasting before the mining cycle can continue. This is especially true for mining that must use large blasting operations in the vicinity of extensive underground workings. In an effort to develop a rational procedure for estimating mine damage produced by blasting, underground rock fall has been assessed for a large-scale blasting operation in oil shale. The amount of mine damage has been quantified in terms of manshifts of effort required to reclaim underground working areas after blasting. This has been further broken down into the three main phases of reclamation, i.e., scaling and excavation, rockbolting, and miscellaneous repairs on ventilation, utilities, etc. Different types of openings have also been assessed including level tunnels, incline drifts and rooms. The effect of repeated blasting on mine damage has also been documented with initial blasts producing more damage than subsequent blasts.

Jan 1, 1988

By John Kemeny

There are many methods used to predict blast fragmentation, including empirical and numerical models, field trials, and experience from ongoing blasting. All of these methods require an accurate measurement or prediction of the rock mass properties. These properties include the characteristics of the rock fractures, including fracture density, friction angle, orientation, length, roughness, fill, etc. They also include the hardness of the intact rock, water content, and other parameters. This paper describes three new technologies that can be used to automatically or semi-automatically obtain rock mass properties: digital image processing, 3D laserscanners, and drill monitoring systems. Each of these technologies is described, including the current state of the art, current limitations, and their future potential. Each of these three technologies has advantages and disadvantages. These new technologies, however, have the potential for providing accurate rock mass information in an automated and real time fashion. This information can then form the basis for a new generation of real-time, database driven blast fragmentation models.

Jan 1, 2004

By Katherine L. Heineken, Timothy J. Tope, Kim David Murphy

One method for small arms disposal is the use of a deactivation furnace or explosive waste incinerator. There are numerous hurdles a facility typically encounters to get the furnace or incinerator fully operational and permitted. For example, one Department of Defense installation was in the permitting process 7 years, which included numerous facility upgrades and modifications. This paper will discuss the technical approach for proactively addressing permitting issues and requirements and will identify potential pitfalls to avoid as well as ways to reduce costs. For example, when determining the waste profile, the facility should forecast its treatment needs (taking into account the net explosive weight limits of the furnace/incinerator) and then classify the wastes into "chemical families" based on the type and composition of the wastes. One waste from each family should then be selected for potential inclusion in the trial burn. Modeling the waste disposal can help to narrow down the number of wastes requiring characterization during a trial burn, as well as the number of analyses.

Jan 1, 1997