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By Brad H. A Brown, J Paul Tidman

To design a blast, one must give consideration to safety, economics, geometry, geology, production needs, and a variety of other requirements. To compare designs requires the time to develop alternatives, analyze, and then improve on them. A number of tools are available to assist with the first set of requirements, however they are poorly integrated. SHOTPlus is a program to improve the efficiency of blasting operations, by combining measurement and blast design tools, and offers the user the time and means to modify designs and explore alternatives.

Jan 1, 1997

By Jackson R. Pressley, M L. Hopkins, R E. Danell, N T. Moxon, Andrew Bowman

Efficient and cost effective blasting is achieved by closely matching the explosive energy to the strength of the material in which it is being used. Although there are many empirical relationships wich approximate this situation complete the blast optimization can only be achieved by quantitatively assessing explosive/rock interactions and explosive performance. The performance of an explosive is essentially governed by its velocity of detonation or the rate at which the detonation wave travels through the explosive column.

Jan 1, 1991

By Kirstin Girdner, Tom BoBo, Brian Norton, John Kemeny

Split Engineering is a truly customer oriented company dedicated to providing quantified fragmentation information of the highest integrity to enable process management and control. Technical decisions, blasting costs, operational efficiency and productivity and equipment performance can all be related to optimum fragmentation. In the past, the lack of an easy, non-disruptive, economical measuring technique has meant that, in most cases, rock fragmentation has not been defined in quantitative terms. Now, the Split-Desktop@ software provides an economical alternative to manual sampling and screening and an objective measure rather than subjective qualitative estimates. This workshop will present the latest features of the Split-Desktop@ software and show users how to quickly get quantifiable results from their blast fragmentation. A step-by-step demonstration will display the software’s flexibility, user-friendly options, and ease of use. Outlining where other mines have benefited from using the Split-Desktop@ software will provide insight to a wide range of software uses and potential applications like creating a database of geologic zone specific post-blast fragmentation information, underground draw point monitoring, stockpile, leach pile, and waste dump size measurement and monitoring, as well as many other applications.

Jan 1, 2000

By Jonathan Peck, Doug Pollitt, Malcolm Scoble

Over the past 5 years the Department of Mining and Metallurgical Engineering, McGill University, has been involved in the performance monitoring of both percussive and rotary drills. Studies conducted in open pit coal and iron ore mines using microprocessor-based research and commercially available instrumentation resulted in the monitoring of at least 6 performance parameters while drilling vertical production blastholes.

Jan 1, 1991

The objective in control blasting is to reduce overbreak to control the final pit wall slope, shaft, drift, ditch, bench, etc. to the final planned excavation limit.

Jan 1, 1990

By John A. Franklin, Tom C. Palangio, Norbert H. Maerz

WipFrag systems I and II have become the world standard in photoanalysis systems to measure fragmentation. Mines, quarries and excavating contractors can now easily measure blast results and track the progress of optimization efforts. This technology was developed and evolved to allow automatic measurements of the size distribution of patiicles on moving conveyors, in truck boxes and on crusher feeds. Production machinery can now be controlled by photoanalysis results and multiple cameras allow various locations to be monitored by a single system. Blast designs can be monitored on a shot by shot basis. Changes in delay times, explosives, patterns and hole sizes can be quickly evaluated. Along with this measurement capability has come a heightened awareness of the importance of “optimum size” and uniformity of particles for lowest cost production and material handling efficiency. In the past, savings in the “drill / blast” cycle of the operation were sometimes overshadowed by downstream production costs related to fragmentation. Now total production costs can be compared with fragmentation sizes which will immediately show the trend towards optimum size for economical production. No cost reduction program can be complete without this critical information.

Jan 1, 1997

There remains considerable controversy in the industry regarding precision type detonators and where the end user can benefit from their use. In spite of the fact that electronic detonators and other prototypes were tested over one decade ago, explosive suppliers have hedged on full scale production for many reasons. Although some of the reasons were based on solid economics, others were strongly influenced by shear internal resistance within the corporate objectives, ultimate fear of market rejection, indecision as to what degree of precision was required and limited data on defining the real benefits to the end user.

Jan 1, 1992

By Agne Rustan

This paper is intended to give a summary of the first ten Symposia on Rock Fragmentation by Blasting where the symposia activities were governed by a Steering Committee replaced at Fragblast 2 by an International Organizing Committee (IOC). At Fragblast 9 the name was changed to Fragblast International Organizing Committee (FIOC). Eighty four pages of statistical data about Fragblast 1-10 is documented on the Fragblast Website (ISEE.org).

Jan 1, 2014

By Charles Barnhart

This paper is a discussion of the causes of deflagration in cast blasting and a description of a project intended to demonstrate how changes in six critical parameters contribute to the deflagration chemical reaction. Control of these parameters is key to solving the nitrogen dioxide “orange smoke” problem. Preliminary results of an investigation into the development of a technology addressing the problem of atmospheric releases of nitrogen dioxide during cast blasting in surface mine operations are described. The project is funded by a $600,000 Small Business Innovative Research grant from the National Science Foundation and an $80,000 Abandoned Coal Mine Land Reclamation Program grant from the state of Wyoming. The presentation will address the measures required to control the blast chemical reaction so that it does not produce nitrogen dioxide through deflagration. Experimental blast data will be focused on a new shaped charge detonation system designed to instantaneously bring the powder column to maximum velocity of detonation (VOD), thus insuring efficient detonation of the entire colulnn.

Jan 1, 2003

By Tristan Worsey, Nathan Rouse, Kyle Hall

Drilling accuracy is the foundation to any successful blast operation. Even the best blasting practices cannot overcome poor drilling and still obtain desired results. Inaccuracies in boreholes can result in flyrock, increased vibration, uneven floor, and other undesired effects. As depth increases, variation in actual burden and spacing is expected even if collars are located precisely. Problems arise when this deviation reaches a point where it adversely affects the function of the blast design. Not only can unsafe conditions such as insufficient burden at the face develop, but poor fragmentation can compound adverse effects. As with any troubleshooting, problems cannot truly be fixed if they cannot be measured. As a result, significant work has been done in the past on this subject. Currently, there are both cheap and expensive methods used to quantify deviation for a given borehole. However, implementation of these techniques is limited. In general production blasts, little is known about the variance in designed versus true borehole geometry. This is especially true if the blaster does not see telltale signs of drilling deviation. However, losses in blast performance may exist and provide an opportunity to obtain better fragmentation and reduce fines. As drill and blast operations strive for better optimization, greater focus is being placed on drilling accuracy and solutions to this problem. The following paper details the use of several current methods for deviation measurement in order to help prevent compromises of safety and improve overall blast performance.

Jan 1, 2018

Choosing the correct delay time for many blasting applications is an important and critical blast design parameter for controlling fragmentation, muckpile shape, swell, digability, throw, ground vibration and airblast. BAl and its affiliates have monitored thousands of full scale blasts in a variety of field conditions, spanning over 15 countries, with sophisticated blast monitoring instrumentation. In some blast environments, a small change in the choice of delay times used had a dramatic and pronounced effect on the overall blast results. In other blast environments, large changes in the choice of delays used had absolutely no effect on the final results in terms of specific outputs. In environments which were sensitive to the delay selection, the type of explosive, dynamic response time of the rock mass (TMIN), integrity of the material, burden and rock mass geometry, all played a very important ,role.

Jan 1, 1998

By Erkan Bayrak, Serkan Erkara, Ozkan Duzgun, Ekin Gungor

This paper presents part of the outcomes of the drill and blast optimization project carried out at Kisladag Gold Mine in Turkey. Kisladag Gold Mine is the largest gold mine in Turkey with a low-grade, bulk-tonnage, open pit operation that uses heap leaching for gold recovery. After blasting, the ore is fed to a three-stage crushing circuit which prepares crushed ore approximately -10 mm (0.39 in) for heap leaching. Crusher downtime analysis showed that blocky material and insufficient feed are causing significant downtimes with the primary crusher. This was supported by the fragmentation data collected to date. It was decided to initiate a fragmentation project to understand the variation in the run-of-mine (ROM) size with a view to provide a consistent feed to the crushing circuit. The study includes the analyses of the ore strength and structure, image analysis of the fragmentation pictures acquired from blasts, blast auditing and quality assurance and quality control (QA/QC) analyses. During this project, over 200 fragmentation pictures were acquired from 47 blasts to optimize ore and waste blasts. Ore strength varies between 30 and 120 MPa and rock quality designation (RQD) ranges between 30 and 100. A site-specific fragmentation model was used to calibrate the fragmentation for blast domains formed. In addition, alternative cases were simulated to achieve blasts designs with consistent ROM fragmentation size distribution. Alternative blast designs that include stemming length and powder factor changes were suggested. Long stemming length, drill cuttings use, free faced blasts, small shot sizes and poor stemming length control were some of the key issues causing coarse fragmentation.

Jan 1, 2015

By Randall M. Wheeler

"Fourier analysis is a very powerful frequency analysis tool. However, it is frequently misunderstood and sometimes used inappropriately. Part of this workshop will involve the basics of Fourier series, the Fourier integral and finally the Fourier transform. Included will be a brief discussion of analysiswindows, including the box and Hamring windows."

Jan 1, 1998

By Chris Uys, Johan Labuschagne

Sishen Iron Ore Mine, located in the Northern Cape, is an open cast mine excavating approximately 100 million tons rock to produce 25 million tons of high grade haematite ore per annum. The size of the pit is approximately 12 km ‘1.5 km ‘150 metres. The final depth is planned to be around 350 metres. It is hard rock mining operation employing the conventional truck and shovel method. Mining benches are twelve and a half metres in height and are divided into blasting blocks, each consisting of approximately 300 000 tons of material.

Jan 1, 1997

By Braden T. Lusk, Shannon P. Lusk, Kyle A. Perry

A high explosives shock tube has been constructed and developed to test blast resistant windows with pressure versus time waveforms similar to waveforms generated by arena testing. Calibration of the high explosives shock tube, or Large Arena Test Simulator (LATS), included numerous tests performed by detonating varying charge weights at different distances from three piezoelectric pressure sensors located at one end of the shock tube (where the test subject would be installed). The maximum reflected pressure and positive phase impulse were calculated for each waveform generated in the tests. Pressure versus distance and impulse versus distance graphs were generated. Results have been graphed in order to predict charge weights and distances that correlate to the desired pressure and impulse at the end of the tube for future tests. This is a valuable tool when testing expensive, job specific components so the loading requirements are met on the first attempt.

Jan 1, 2010

By Jackson R. Pressley, Bruce Vandenberg

The knowledge of how and when your explosives go off can help you make intelligent decisions regarding future application of explosives thus removing some of the black magic associated with blasting. The net result will be intelligently set-up shots with timing, explosive charges, and placement more accurately done. Lower operational costs can be achieved when the correct combinations are applied.

Jan 1, 1992

By B. Papilon

Dynamic pressures during blasting can affect performances of both electronic and non-electronic detonators. Boreholes can develop tremendous amount of pressures during blasting. The effect of such elevated pressure especially during electronic delay countdown is probably more acute in electronic detonators. Measuring the pressures during blasting can aid to understand the relationship between magnitude of the pressure developed and the multitude of blasting conditions.

Jan 1, 2013

By Pat McLaughlin

Blast design in the construction industry has often been based on past practice or powder factors. This is to some extent understandable, since construction projects do not have the longevity of mining or quarrying operations and therefore have less opportunity to pursue potential improvements. The main concern of the operator is whether or not the technique will work, and at what cost to the downstream processes. Time, not long term savings, is of the essence.

Jan 1, 1994

By Steve Collinsworth, Nils Heinke

In 1989, I realized the definite need for change in the Blast Hole Drilling Industry. With over 25 years of experience in dealing with the industry, I am well inGormed and educated concerning the problems that occur in Blast Hole Drilling. After continues interaction with the Drill & Blast Superintendents, Drillers, Purchasing Agents, Mechanics, and others in the field, a basic understanding was developed as to the origins of the main problems that the industry f&s with their drillings programs.

Jan 1, 1997

By Claude Cunningham

The primary reason for blasting is to fragment rock. In production blasting, the fragment sizes produced are known to exercise an overwhelming influence over working costs: handling costs and tonnage throughput are directly affected by secondary breaking, loading and crushing, all functions of fragmentation. In addition, particular size fractions are frequently of intense interest in terms of market or process requirements.

Jan 1, 1995