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By Dale Preece, Stephen Chung

Mining and quarrying industries recognize blasting as the most effective method for breaking and removing large volumes of rock. However, the economics of blasting are often offset by the costly trial-and-error approach. Researchers in the field of blasting therefore design models to help eliminate the number of trials before finding the best feasible solution. Because of the complexity of blasting, a capable model would allow the designer to look at more than one variable at a time so that the most critical factor can be tackled.

Jan 1, 2002

By Josh Campbell

Modern blast engineering involves the use of modern technology to provide more efficient blasts. Through the use of improved measurement techniques more information can be obtained on many of the physical variables of a quarry rock face. By employing this information, a more efficient production shot can be designed and loaded. Along with improvements in production, greater safety and improved environmental impact can be achieved. This paper concerns the employment of modern blast engineering at a granite quarry in the Southeastern United States. The test period extended over a period of approximately six months, and this paper will show the results achieved in that time span.

Jan 1, 1998

By Paul Worsey, Larry Kenchel, David Randall, Mark Schmidt

The University of Missouri-Rolla (UMR) has historically maintained a manual, paper inventory of explosives stored and used at the university. Although this system was accurate for inventory control and reporting criteria, it was labor intense and delays in record keeping were predominant. A directive from the university’s administration mandated the development of a precise real time system “on-line” to maintain and control the explosives inventory in line with the universities new chemical tracking policies.

Jan 1, 2001

By J Paul Tidman, Stephen H. Chung

One of the requirements in open pit gold mines is to minimise the mixing of ore and waste. Dilution can be reduced by choke blasting and control of the initiating sequencing. The authors have used the DMC computer model (developed at SANDIA) to examine the effects of timing and charge distribution on ore dilution. The model has been calibrated by measurements of vertical uplift derived from high speed videos made at the Dome Super Pit in Timmins.

Jan 1, 1997

By Jorge Cardenas, Diego Sanchez

Maximizing SAG mill throughput and metallurgical recovery in hard rock operations requires achieving target fragmentation, particularly a sufficient proportion of fines (<25.4 mm). These fines thresholds are strongly influenced by rock mass competency, commonly characterized using the Axb parameter (30–70) from the JK Drop Weight Test. In many operations, conventional blasting designs and standard emulsions fail to generate the fines content required for efficient downstream comminution. This study evaluates several advanced blasting strategies aimed at enhancing fines generation in very competent rock masses while maintaining cost-effective drill and blast performance. The first approach focuses on steadily increasing the powder factor (kg/t) as a core strategy, complemented by adjustments in blasthole diameter, reduced burden and spacing, the use of dual initiation points, short inter-hole delays (<25 ms), and optimized sequencing—all aimed at enhancing energy distribution and maximizing fines generation in highly competent rock masses. The second strategy consists of increasing the energy factor (kJ/t) by selecting explosives with higher energetic content and detonation performance. This includes the use of heavy ANFO blends and ultra high-energy emulsions with aluminum-based formulations, achieving Relative Bulk Strength (RBS) values between 180–190 and up to 210–230, respectively. These products offer higher detonation velocity (VOD) and peak pressure, enhancing shock energy transmission and breakage efficiency. Field results in granodioritic porphyries with high uniaxial compressive strength showed a 3–5% increase in fines generation compared to standard emulsions—contributing directly to meeting mill performance targets in high Axb conditions. Combined, these strategies provide a practical and technically validated pathway to achieving fines generation targets required for optimal mill performance. When matched to site-specific rock mass characteristics and integrated with blast monitoring tools, they enable improved fragmentation control, reduced P80, and enhanced plant throughput—without compromising operational efficiency or increasing costs disproportionately

Jan 26, 2026

By Joseph A. Sohara, John J. Mullay, Curtis J. Keefer, Robert L. Schrepple

The desensitization of an explosive column by the action of a previous detonation (adjacent borehole, deck or detonating cord) is a vital concern to the explosives industry. Previous reports to this symposium and in other places have addressed this issue. However, this work has been mainly concerned with model or simulated conditions. No systematic study has appeared that utilizes an actual borehole environment. Thus the relation between this work and expected field performance is somewhat uncertain. The present paper attempts to partially resolve this difficulty.

Jan 1, 1990

By Michael E. Kovach

This discussion is an overview of an approach to drilling and blasting angle holes at Martin Marietta Aggregates. Method of determining burdens, hole depths, angle settings and explosive selection will be discussed in detail with an emphasis on safety and production. Such techniques and methods involve the use of hand-held surveying instruments such as the Abney level, pocket transit and inclinometer along with measuring tape and burden pole. An interesting method developed by Oscar Banfield a retired Martin Marietta and E. I. duPont engineer, for setting the proper angle on a drill will also be presented. This treatise is a discussion of the use of simple yet important tools and techniques a blaster should use to resolve both routine and complex problems encountered during quarry blasting operations.

Jan 1, 1992

By O E. Crenwelge

Seismograph measurements are usually made near blasting operations solely for the purpose of monitoring compliance with governmental regulations. However, recordings of seismograph signals have far greater potential than this, if the proper procedures are used for analyzing the transient data.

Jan 1, 1991

Increasingly specialized blasting needs require that the explosive energy available in a borehole be reliably known for representative blasting conditions. The underwater test, when properly performed, can yield such information and thus provide a reliable rating of explosives in terms of energy release. This paper reiterates the stringent experimental conditions to be satisfied, and data analysis and interpretation techniques to be followed to achieve this. This is supported by detailed experimental studies involving select parameters in both detonator and booster sensitive explosive compositions. The paper also illustrates the inadvisability of equating blasting performance with the commonly calculated energy values.

Jan 1, 2000

By Jeff Wachendorf

As the title "Cast Blasting Around Town" implies, this paper details the starting of a cast blasting program in and around the town of Colstrip, Montana. As strip ratios have increased, the need to adapt and find solutions to provide coal at a reasonable cost to the captive power plants has risen. Colstrip, Montana has a long history of coal mining which dates back to the early 1920's when Foley Brothers began supplying coal strictly for powering locomotive engines. Early mining days starting in the 1920's and the progression up through the 1970's when mine mouth power plants were built will be discussed. To accomplish the desired results, early mining techniques included steam and electric powered equipment as well as a lot of actual horse power.

Jan 1, 2009

By Charles H. Dowding

Public concern over blast-induced CRACKING has led to the search for a radically new approach to vibration control. The present system, while scientifically correct, is cumbersome to explain. Historically the potential for blast-induced cracking has come to be described through velocity time histories, which are correlated with observation of crack extension under controlled experimental conditions. Unfortunately time histories are simply too difficult for jurors and village or county regulatory boards to understand. Furthermore these arbiters must accept on faith that the observers were unbiased. Since these public bodies control the manner in which blasting activity is adjudicated and regulated, information must be presented in a form they can understand and that is not subject to second-guessing.

Jan 1, 1999

By Thomas L. Barkley, Michael A. Indihar

The new Cyprus Northshore Mining Co. has taken the previous blasting methods of Reserve Mining Co.'s mine in northern Minnesota and adapted them to a new competative Iron Ore Industry. Cyprus was challenged to develop new blasting methods to reduce costs and improve results over the previous mining operation. Many of the older procedures have been kept, but others have been changed in ways that bring the mine operation up to state of the art technology. In addition, unique ideas not previously tried in the North American Iron Ore Industry have been instituted. So far, this has reduced Cyprus's blasting costs by 70 percent.

Jan 1, 1991

By Calvin J. Konya

There have been many different brands of high precision caps introduced on the US market in the last five years. High precision timing definitely effects the performance of the blast. One should be able to optimize fragmentation and minimize environmental effects with the use of high precision caps and selection of the proper time period. The consumer who purchases the caps may not be fully aware of the tolerances in firing times of caps used in the field. This paper will discuss results of field tests of cap tolerances from an independent study conducted by Precision Blasting Services.

Jan 1, 1989

By Justus Deen, Paul V. Sterk

Through the 119 year history of the Homestake Mine various methods of raise mining have been used, these include conventional, bored, and drop raises. These raises provide passage for men and supplies, provide ventilation, transfer broken rock from level to level, and serve as emergency escapeways. As the 1980s came to a close, many of the larger ore bodies in the mine had been mined out. This has resulted in many crown pillar situations that required a method to mine them. In addition, the Homestake ore body also contains numerous ore reserves that have short vertical height. The ore itself can be from vertical to 50 degrees in dip. Due to the high cost of drift and ramp development many of these ore bodies are sub-economic using conventional mechanized cut and fill mining.

Jan 1, 1996

By Zhang Zhenyu, Wu Xinxia

The blasting quarrying technology of rock material of rock-fill dam is one of the more complex problems in the field of engineering blasting at present. The Kuz-Ram model is not suited to predict fragmentation distribution under the geology condition of Tianshengqiao(TSQ) fist-step power station. The modification of kuz-Ram model is discussed. With reference to the idea of model establishment of Kuz-Ram model and according to the results of experimental blasting in-situ, two fragmentation prediction models-TSQ-1 and TSQ-2 model are presented which are adapted to the particular condition of rock material querying blasting of rock-fill dam with concrete facing of TSQ first-step power station. The rapid judgment method of qualified grade material and the method of optimizing blasting parameters are also presented in this paper.

Jan 1, 1998

By R Ludeling, Klaus G. Hinzen, Ulrich Steiner, Friedrich Heinemeyer, Peter Roh

A method for hybrid modelling of blast vibrations in time domain is developed. Field seismograms of single shot experiments are combined with computer simulations. In this way firing times of blastholes in a pattern can be optimized due to diverse criteria like maximum velocity amplitude and frequency content of the vibrations.

Jan 1, 1987

By Mark S. Stagg, Stephen A. Rholl, Steven G. Grannes

A method of determining the fragment size distribution of rock quarry muckpiles using photographic and digital-image processing techniques has been developed by the Bureau of Mines. To assess the fragmentation, photographs and video tapes were taken in both the laboratory and in the field and then digitized for analysis. The fully-automated process uses specially written image-interpretation software which had been developed previously by Bureau researchers to measure irregular taconite ore shapes. The advantages of photographic assessment in comparison with other methods include speed and cost.

Jan 1, 1993

By Q Liu, P D. Katsabanis

The energy output of crushed AN/FO, crushed AN/FO mixed with Aluminum (5%, 6.4% and 9.4% A1 by mass) and a commercial emulsion explosive has been measured using a detonation calorimeter. The charges had a diameter of 10 mm and were heavily confined by a 11 mm thick copper shell. In order to achieve stable detonation glass microballoons were used in the explosives so that the density of the AN/FO charges would be around 1.1 g/cc. The charges were detonated in vacuum and the detonation products were analyzed using gas chromatography. It was found that energy values were very close to calculated values obtained by ideal detonation codes.

Jan 1, 1993

By George P. Jr Schivley

Data is presented showing Penetration Rate (PR) versus Force-on-the Bit (FB) and Bit Angular Speed (N). Using this data, it is shown how FB and N each uniquely contribute to the PR for any particular drilling situation. This data represents many mining situations; including coal, copper, gold, iron ore and limestone quarrying. The important relationship between Penetration per Revolution (P/R) and the height of the cutting elements of the bit (CH) is discussed. Drill performance is then reviewed, considering the effect of FB and N on bit life. All this leads to recommendations for the operating values of FB and N for drilling situations where the rock is not highly abrasive and bit replacements are because of catastrophic failure of the bit cone bearings.

Jan 1, 1995

By J Mensah, G C. Sen

Often large boulders of rock have to be fragmented in civil or mining engineering operations. These oversize boulders are encountered after primary blasts in both surface and underground excavations of minerals. Various methods are employed to break large boulders into a manageable size for loading and crushing. These methods range from mechanical breaking (such as drop-ball and hydraulic impactor) to the use of explosives. Apart from these, static agents (such as expanding chemicals) are used in special circumstances.

Jan 1, 1989