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By Bill Birch, Toby White, Ian Brown

costs/benefits of electronic detonators and measure their effects on primary crusher productivity. 9 blasts (3 shock tube blasts, 6 electronic blasts). Measured electricity consumption & primary crusher throughput. Change to Electronic Detonators resulted in a 7% reduction in primary electricity costs and a 15% increase in primary crusher productivity.

Feb 1, 2020

By Steve Collinsworth

Sometimes, for those of us in the right place at the right time with the right product, necessity creates opportunity. Such is my case at a West Virginia coal mine where a mine manager was desperately seeking a way to eliminate coal damage on cast shots while maintaining cast percentage without the expensive process of secondary drilling. This paper will focus on how bottom hole air decking is solving the problem.

Jan 1, 2000

By Lon Santis

This paper analyzes 110 serious accidents that occurred during the use of commercial explosives in mining, construction, and other industries since 1992. Data from the Mine Safety and Health Administration (MSHA), the Institute of Makers of Explosives (IME) members’ reports, and media reports were used. Only accidents that resulted in a fatality, significant lost work time, or injury to the public were considered in this analysis. The accident data were analyzed for trends in frequency, type of industry, cause, type of individual harmed, and geographical region. Although the data showed that explosives accidents are decreasing in frequency, still, 29 people were killed and 134 injured. Eightyfive of the accidents occurred in mining, 17 occurred in construction, and 8 occurred in other industries including oil recovery, seismic exploration, agriculture, logging, boiler cleaning, and avalanche blasting. As other studies have shown, flyrock and failure of blast area security caused over half of the accidents. Mishandling, misfires, or fumes caused just over one-third of the accidents. Lightning and drilling into explosives were responsible for the remainder of accidents.

Jan 1, 2003

By Ian Bell, Shahram Tafazoli, Bahram Sameti, Aylin Azmin, Edmond Chow, Nima Ziraknejad

Image-based rock fragmentation analysis methods have been applied by blast engineers to estimate rock size distribution for over 25 years. These methods utilize a wide range of image segmentation techniques, from manual to fully-automated, to delineate the edges of the rocks in the image. In most commercially available image-based rock fragmentation analysis systems, rock delineation results are converted to physical rock sizes by introducing one or more reference objects (e.g., basketballs or other objects with known geometry) to the scene as size-scaling references.

Jan 1, 2014

By L. A. Heim, E. A. McCullough, N. J. Amiotte

The explosives industry is subject to the laws of multiple jurisdictions, which means that several regulatory agencies are responsible for governing different aspects of the commercial explosives industry. Among these regulators are the Mine Safety and Health Administration (MSHA) who implements codes that better ensure both occupational and public safety which is influenced by professional blasting projects and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), who enforces commercial explosives storage and security, among other responsibilities.

Jan 1, 2014

By Kyle Apple

The following is a case study of how LuckStone Corporation improved their blast monitoring and documentation program. A number of resources already at their disposal have been utilized to improve the body of data collected from each blast. The tools being used include GPS, aerial photos, and a user-friendly push button format excel spreadsheet. The data collected include product by product records of materials used, distances to all concerned neighbors, seismograph data, etc: The spreadsheet has been designed to perform an ongoing analysis of blasting trends. The program has been carried out at a corporate level and is in use by blasters at each location. This paper addresses the advantages and drawbacks of this program. It also addresses the ways in which the various tools were integrated, Discussed as well is the need for simplicity when bringing “new” technology to the field and the steps taken in familiarizing the end user to changes.

Jan 1, 2001

By Thomas L. Barkley

My historic auditing of Underground Drilling and Blasting Practices has demonstrated to the author the need for reviews of many mines' procedures in these processes. Poor understanding of the basic principles and practices of the drilling and blasting science in Underground Development Mining has created significant costs to mining operations in many instances.

Jan 1, 2019

By Xue Yongpeng, Zhu Zhenhai, Zhu Ming

The purpose of the Solid Medium Controlled Blasting Technique and Its Applications is to have the inside of the vessel-shaped framework (e.g: oil tank , water pool, gas chamber, chimney, water tower, grain warehouse and etc.) or the one side of the thin wall-shaped structure(e.g: steel bar concrete wall and etc.), both of which are intended to be demolished, inserted with the required solid medium (e.g: soil , sand , coal, salt and etc.) ,in which there is a certain mass density, and then through which the blasting energy is transferred to fulfill the blasting task. For such a technique, it is necessary to bury the explosives into the inserted solid medium and then to start the explosion to blast the intended target into pieces. The filling of the solid medium may be done mechanically or by man. Compared with the water pressure blasting technique, this one has the characteristics of good effect. wide application, simplified construction procedure , safe and reliable operation and small vibration (less vibration than water pressure blasting by 80% to 90%)in particular without any flying stones, thus resulting in better and comprehensive social and economickfficiency.

Jan 1, 2000

By Ray Slavin, Remi Proulx

The Meikle Mine is a mature underground gold mine utilizing primary and secondary longhole open stoping method with delayed backfill. Combined production with the newly developed Rodeo Mine is 4700 tons per day (4265 tonnes per day) of ore. The vast majority of Meikle Mine production comes from secondary and remnant stope blocks. Remnant stopes are ore blocks that were left behind in the initial mining sequence due to various reasons. Mining of these remnant blocks has created many challenging blasting situations. The application of electronic initiation to blast remnant stopes has proven extremely beneficial. Electronic initiation has provided the blasting engineer with a high degree of flexibility with respect to timing to successfully extract these difficult stopes. Post blast assessment of the remnant stopes using the mine’s cavity monitoring system (CMS) demonstrates that the mine is maximizing ore recovery and minimizing waste dilution. The largest remnant stope blast to date required 54 holes and produced 6700 tons (6075 tonnes) of ore. Another area where the application of electronic detonators has proved successful is in the extraction of slots in which ground conditions are extremely poor. Taking the slot blasts in one shot with double-decked holes as opposed to two single-decked shots has eliminated the need to clean and or re-drill holes. The ability to open the slots in one blast has helped reduce the total mining cost. This concept has recently been expanded to blast complete stopes in one shot. This reduces the stope cycle time considerably and allows the mine to bring ore forward. Current plans for 2004 are to excavate 50% of mine wide stope production using electronic initiation technology.

Jan 1, 2004

By Egonk Arriagada, Jair Alarcon

The efficient use of energy in the ore comminution process is an increasingly important strategic issue for improving the productivity and competitiveness in the mining industry as is in recent years the related focus on reducing energy intensity on the atmospheric pollution and greenhouse gas emissions from its use.

Jan 1, 2015

By W C. Brukle

Our title for this presentation could be taken in many ways. One course would be terrifying and that would be to cite incredibly bad practices. All of our votes/efforts should be for the reverse direction in which everyone does his/her best to keep their pit or working place free from hazards.

Jan 1, 1983

By Norman Paley

A blasting project was undertaken at the Teck Alaska Red Dog Mine to determine the extent that Semi-Autogenous Grinding (SAG) mill throughput could be increased by using electronic detonators. The Julius Kruttschnitt Mineral Research Centre (JKMRC) blast fragmentation, jaw crusher, and SAG mill breakage models were used to relate changes in the blast fragmentation measured with the SPLIT image analysis system to the SAG mill performance. For optimum performance a SAG mill requires a particular size distribution; a number of large rocks to facilitate breakage by impact, as few as possible middle size rocks that become critical size, and the maximum fines which will pass quickly through an open-circuit mill. Physical constraints of drill and charging equipment size limit the extent that pattern geometry can be changed, and the powder factor increased, to maximize fines. However, a growing number of studies have shown that the use of electronic detonators can lead to increased fragmentation and greater muckpile uniformity, providing an alternate means of increasing primary breakage by blasting. Unfortunately results in the literature rarely quantified the changes to the fragmentation distribution. The measured gyratory crusher fragmentation of 2,750,000t of ore was used to compare stockpiles constructed from shots using pyrotechnic detonators to those using Orica i-kon electronic detonators. In the first stage of the study, stockpiles shot using 25 ms inter-hole timing with pyrotechnic detonators were compared to stockpiles shot using the same inter-hole timing with electronic detonators. In the second stage of the study, stockpiles shot using 17 ms inter-hole timing with pyrotechnic detonators were compared to stockpiles shot using 8 ms inter-hole timing with electronic detonators. When electronic detonators were used with the inter-hole timing kept constant, fragmentation uniformity was slightly increased, but mean fragment size increased by 20%. When electronic detonators were used with faster inter-hole timing, fragmentation uniformity was slightly reduced, but mean fragment size decreased by 30%. Modeling was used to determine the SAG mill throughput which could be expected from this change in fragmentation to determine the pairs of pyrotechnic and electronic blast pattern geometries that would provide similar throughput. The economic benefit from the electronic detonator shots was calculated to assist in determining the optimum blast designs for their use.

Jan 1, 2010

By Rodney Pinksen, Remi Proulx

The IOC Mining and Operations Departments expressed an interest in reducing the amount of oversize material (>1.0 m x 1.0 m x 1.0 m; 39 inches x 39 inches x 39 inches) being produced and its subsequent downstream effects including in-pit sorting and reduction, damage to mobile equipment, and significant delays in the loading pockets and the primary crushers. To achieve this goal an oversize reduction project was undertaken by the mine and to date has significantly improved upon baseline measures.

Jan 1, 2011

By Robert Boehnke, Bernd Mueller

This contribution presents an innovative, statistically supported method to predict blast vibrations in rock mass. For modelling the processes during and after detonation, a theory is employed which is based on linear momentum (so-called momentum theory), strongly supported by new measurement methods. During the course of the investigations, the following parameters have been found to dominantly influence vibrations: ! charge WB, includes geometrical factors such as borehole length and diameter (kg) ! detonation velocity cd of the explosives used (m/s) ! distance r between the points of emission and immission (m) and the statistically determined negative exponent n ! factor RM or RS of the rock mass which is related to the specific blast momentum and the drilling and blasting technique used and is statistically determined together with the exponent m (mm/kg or mms/kgm)

Jan 1, 2004

By Quentin L. Rhoton

"The use of explosives in a surgical manner was approved to facilitate, due to time constraints, anextremely significant paleontological find in the Plunket Point area of the Dominion Range, Antarctica. The organic material revealed by surgical blasting techniques may have altered basic scientific dogma on Antarctic glaciation theory."

Jan 1, 1999

By M. S. Dotto

The knowledge of the explosive/ rock mass interaction process is important in predicting blast performance. It includes understanding rock properties, energy usage, and attenuation in the rock mass. The paper proposes a method to quantify blast-induced rock mass damage from the field measurements and apply it to modeling blast fragmentation.

Feb 1, 2020

By Peter Moser, Finn Ouchterlony, José A. Sanchidrián

"Blast fragmentation data in the form of percentile fragment sizes as function of specific charge oftenform a set of straight lines in log(size)-log(energy) space that tend to converge on a common focal point.Single-hole shots in specimens of virgin material clearly show this and the phenomenon is called the fragmentation-energy fan. Field data from bench blasting in rock scatter much more but may be interpreted to form such fans. The slopes values of the fan lines depend primarily on the percentile level. This property can be derived from sieving functions of the form P[ln(x/xmax)/ln(xmax/x50)]. An example is the Swebrec function when the parameter b is constant."

Jan 1, 2017

By Kaushik Dey

Bord and pillar is the most predominant method of wining of coal in Indian underground coal mines. Development heading in coal mines often encounters roof stability problem and results in roof overbreak. Research on this reveals that the blast-induced ground vibration may have significant contribution in roof overbreak, especially, when solid blasting is carried out in the bord and pillar method. Solid blasting, in general, is associated with higher charge confinement due to lack of free face and generates higher ground vibration, which in turn results in excess overbreak.

Jan 1, 2008

By Ian Bell

This paper investigates fragmentation in an aggregate quarry using the fragmentation-energy fan concept. Six blasts were monitored, located one behind the other in the same quarry area. The rock structure was blocky, the water level and the usage of explosives were variable within and between the blasts. The powder factor above grade was between 0.28 and 0.44 kg/m3 (0.47 and 0.74 lb/yd3). Fragmentation of the plant feed was measured using an online digital image analysis system and three belt scales. The oversize material that was not directly fed to the plant after the blast corresponds to 3‒9.3 % of the total. Data from image analysis was used to build the size distribution in the coarse range (fragments above 120 mm), and the passing fractions at 120 and 25 mm (4.72 and 0.98 in) obtained from belt scales data were used in the range 120‒25 mm (4.72 ‒ 0.98 in) . The non-dimensional percentile sizes between 10 and 90 % for each blast are described through power functions of the powder factor above grade; the model coefficients are statistically significant. From them, using the principles of the fragmentation-energy fan and the Swebrec distribution properties, the fragmentation can be expressed in terms of the powder factor by means of five parameters: the fan focus coordinates and the three parameters of a function of the exponents vs. the percentage passing. The model shows a good capability to describe fragmentation.

Jan 1, 2019

By David E. Siskind

Increased mineral consumption and environmental concern have caused much interest in potential damage and annoyance from ground vibration and airblast produced by production blasting in surface mines and quarries. Ground vibrations are traditionally blamed for "shaking the house to its foundations," but often the airblast is responsible, particularly when the distances from mine to structure are large. Simultaneous measurements of ground vibrations, structure vibrations, and indoor and outdoor noise from blasting are being used by the Bureau of Mines to determine the relative importance of the ground and airborne blast energy in shaking the structure and making windows, dishes, etc., rattle.

Jan 1, 1977