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By M. Szumny, P. Mertuszka, K. Fuławka

Multi-face destress blasting is the basic method of reducing rock bursts hazard in Polish copper mines. Blasting operations of this type are carried out regularly, twice a day in order to minimize the geomechanical threat while maintaining high extraction efficiency. Unfortunately, the assessment of the effectiveness of this type of work until recently was based solely on determining whether a given destress blasting triggered a seismic tremor or not. Information on the characteristics of seismic waves generated by blasting has so far been omitted in analyzes of this type. The lack of reliable knowledge about the generated seismic effect makes the introduction of constructive corrective actions impossible, which in turn significantly reduces the triggering potential of conducted destress blasting. This study presents the results of comprehensive work aimed at increasing the effectiveness of active rock burst prevention in Lubin underground copper mine. For this purpose, an innovative system for continuous monitoring of seismic waves induced by multi-face blasting was developed, and a new method for seismic assessment of the effectiveness of the destress activities was developed. Based on the monitoring data and the comprehensive analysis of waveforms, the effectiveness of individual blasting operations was determined, and on this basis, modifications to the drilling and blasting patterns aimed at increasing the generated seismic effect were proposed. The use of innovative methods of monitoring and data analysis made it possible to increase the effectiveness of the conducted activities, in terms of the magnitude of seismic vibrations, up to 250%. It should be emphasized that the introduced modifications were aimed at increasing the effectiveness of blasting operations while maintaining the current level of costs. As a result, the proposed solution turned out to be highly effective, significantly affecting the safety of the work carried out in Polish copper mines. Thus the proposed approach is planned to be implemented in other Polish copper mines belonging to KGHM in the near future

Jan 1, 2024

By Cristian Rodriquez, Fernando Fernandez, Rodrigo Fuentealba, Tom BoBo, Maria Rocha, John Kemeny

This paper describes a case study that was conducted at a new mine in South America. This mine has significant geologic variations that will result in different distributions of hard and soft ore being mined at different periods of time over the mine life. A study was conducted to determine the optimum blast design that will meet the mill throughput requirement of 95,000 tonnes (104,720 tons) per day for the first 10 years of the mine life. As part of this study, field rock mass characterization and laboratory tests were conducted. This includes standard rock mechanics tests as well as rock breakage tests used in mill simulations. The geology of the ore body was broken up into four Geologic Units, and statistical variations in the properties were determined for each unit. Using this data along with the data on the occurrence of the different geologic units over time, simulations were made of the run-of-mine (ROM) fragmentation due to different blast designs, and these results were used in simulating the resulting throughput after crushing and grinding. Four blast designs were considered with powder factors of 0.44, 0.54, 0.64 and 0.94 kg/t. The results of this study show that determining the proper blast design is important in ensuring that the mill throughput requirement will be met over the mine life.

Jan 1, 2015

By Diego Quezada, Carlos Munoz, Marco Arellano

It is well-know that the presence of fine materials in mining has a direct impact on the plant processes with a great influence in the total amount of ore production and recovery. In Cu mining heap leaching is affected negatively by the presence of fines material (< 100 # Ty) in leaching piles, where a decreasing in Cu recovery is achieved in a lot of cases. D&B practices used normally in mine operations can generate fines > 4% in blasted piles, but the principal effects are reflected in the downstream processes where pre-conditioning post-blast materials release greater quantities of fines.

Jan 1, 2010

By B Mohanty

The current basis for rating of commercial explosives is examined, with particular emphasis on calculated bulk and weight strengths, detonation velocity and underwater energy measurement. The calculated strengths still form the basis for selecting explosives for most blasting applications, with the measured detonation parameters serving only as a measure of the quality of the explosive. The major drawbacks with this approach are discussed, in view of the non-ideal nature of commercial explosives and the field conditions prevalent during the blasting operation. A unified approach to rating explosives on the basis of blasting performance rather than calculated energy alone is presented for various types of explosives. This incorporates the relevant field parameters as well as the effect of non-ideal reactions, both of which affect explosive energy release and its transfer to target rock.

Jan 1, 1988

By Nan H. Lee, Christopher J. Hunter, Stephen H. Chung

Several factors affect the productivity of mining operations. The geological structure of a mineral deposit and the fragment size of blasted material are considered to be most influential. It is well known that productivity varies with mucking cycles and that this is related to the explosive energy produced by a blast.

Jan 1, 1991

By W. J. Birch

The dedicated documenting of blast design and vibration monitoring results forms part of the best practice methodology for today’s blasting operators. This allows regression curves to be constantly updated and in turn compatible charge weight determinations are based upon the most current data. The point can arise however when so much data becomes agglomerated that variations in blast design, geology or monitoring location response and their effects can pass unobserved and start to have an adverse effect on the forecasting capability of the regression due to a deterioration of the standard error statistic. The simple solution would be to only compile like-for-like blasting returns, but this prospect can quickly become unworkable due to the number of potential variables. In addition it is very difficult to spot subtle variations by simply examining a standard scaled-distance curve mainly due to the intrinsic data scatter that is always present together with the logarithmic nature of the regression curve. If indeed a variation is thought to be apparent, how can the degree and magnitude of its influence to be quantified? The Likelihood Ratio Test when applied to regression data can diagnose subtle variations between data sub-sets and provides a comparative statistic as to the degree of variation. By analysing datasets in such a way, levels of compatibility are obtained, indicating which sets can be combined in order to increase prediction capability.

Jan 1, 2004

By Satish R. Kate

Explosive is a chemical energy, which on detonation is released instantaneously with extremely high speed and under high pressure. It is used to meet the basic requirement for breaking of rocks. The productivity is the function of Drilling, Explosives and Fragmentation. Thus, the quality of explosives (energy content) is the key to get desired fragmentation. The variation in energy of explosives and volume of rock per hole have direct impact on fragmentation and cost of excavation (drilling and explosive costs). With the application of higher and higher energy content explosives, it is possible to expand the drilling patterns, i.e. volume in cum. per borehole. As such, higher drill productivity and higher production from the given number of holes can be achieved by adopting appropriate energy content in explosives, and suitable drill pattern for getting desired fragmentation.

Jan 1, 1998

By Earl C. Hutchison, John Loviza

At the Metropolitan Nashville International Airport, with its more than 600 scheduled daily flights from American Airlines hub operations, other scheduled airline flights, Tennessee Air National Guard operations, as well as numerous industry air flights, the excavation of 300,000 cubic yards of rock was required without disrupting airport operations for a cut and cover underground tunnel with a 4 lane US Highway and new airplane runway to extend across it's top. In addition to the excavation, the removed rock was to be broken to specification type that was clean and of small size for fill in another area of the airport property. The blasting was limited to two 1/2 hour windows per day and stiff monetary penalties were in place for schedule slippage of each phase of the project.

Jan 1, 1992

By Oldrich Machacek, Gary R. Eck

The underwater detonation test method has been long recognized as a useful tool for the evaluation of the energy release and relative effectiveness of commercial explosives. In this study, underwater energy tests were performed for emulsion and watergel commercial explosives in comparison with ANFO. Heavy ANFO type blends based on emulsions and watergels were also investigated under and without confinement.

Jan 1, 1990

By G. R. Adhikari

A major part of mineral production comes from surface mining and there has been a rapid growth in this sector with the deployment of high capacity equipment. The importance of blast design combining appropriately both theoretical methods and practical approach has been well recognized in the field of surface mining. It is known that blast design has a direct consequence on productivity, safety and economic viability of these mines. Blasting is the most common method of breaking rocks in mining, but it has to be cost-effective. In coal production, for instance, drilling and blasting account for 25 percent of the total procution cost. In hard rock mining, the cost of drilling and blasting is about 40 percent. Due to ever increasing concern for cost-effectiveness together with environmental consciousness, designing blasts for each application has now become a stringent requirement and indeed a challenging task as well.

Jan 1, 2002

By Sebastián Seria, Jorge Álvarez, Diego Cáceres

The capacity to break the rock into adequate size fragments and in a cost-effective way is one of the main challenges in large open pit copper mines in Chile. That capacity is often compromised by the accuracy of geological estimations and the resources allocated by the mine site to update those models, making the blasting design highly dependent on that input and in consequence, blasting results. Given these opportunities, having an alternative method to input estimated key geological parameters allows blast designers to modify their designs and apply the appropriate energy to achieve the desired results. By using measurement-while-drilling data from boreholes and a few samples of actual, widespread, hardness measurements on site, we can deliver an updated cost-effective hardness estimation that is used as an input to improve the blasting design and its results on fragmentation. This estimation is delivered as a hardness interval – often in MPa units- related to the position of actual drilling measurements. In addition, having a sufficiently large drilling dataset allows us to predict hardness in new, undrilled areas near already measured boreholes, serving as a prior estimation available before pattern design. The use of these estimations, applied to several copper mines in Chile, allow us to more accurately determine explosive amounts and borehole drilling, which directly contributes to more productivity and efficiency in mine site operations. The results are often related to narrowing the gap for fragmentation results, even so, in some cases that will be related to direct savings in Drilling & Blasting process in a range 5-10% of the budget, due to powder factor changes.

Jan 26, 2026

By R Yang, P D. Katsabanis, W F. Bawden

Understanding the mechanisms which are taking place during the propagation of a stress wave generated by an explosive charge is of high importance in the detection, characterization and prediction of blast induced damage to the rock. Vibrations caused by the detonation of an explosive are suspected to contribute significantly to the extension of the damage zone. Vibration monitoring close to a blasthole is a relatively new field of research, the hindrance being the scarcity of transducers capable of sustaining extreme accelerations without damage. This paper focuses on the vibration monitoring aspect of a blast induced damage study; the experiment took place at Queen's test site and was meant to record near-field vibration as close as 1 m from 100 mm diameter blastholes.

Jan 1, 1993

By Kenneth Medearis

The accurate prediction of possible damage to historic structures subjected to blasting-related ground motions is not infrequently the dominant factor in whether or not a mining or quarrying operation is allowed to proceed. A recent scenario involving an 1802 Pennsylvania Historic House was resolved satisfactorily, primarily because of the use of modern structural dynamics analysis techniques rather than simplistic peak particle velocity guidelines. One of the associated dominating factors was the truly significant agreement of the analysis results and the values obtained from actual on-site test shot blast motion recordings.

Jan 1, 1993

By S C. Brashear, D A. Anderson, A P. Ritter, S R. Winzer, R Broughton

Results of quarry blasts can be quantified to show the effects of controlled variables. Two studies have been carried out: one to document the effect of delay on fragmentation and the other to show the effects of higher relief patterns and more accurate initiators. By using such techniques as highspeed photography and timing studies of mucking and crushing operations, subtle differences in blasting efficiency can be measured and quarry blasting can be optimized. Given the range of available and developing blasting technologies, quarry operators should resort to quantitative analyses of their blasting practices to get maximum productivity.

Jan 1, 1985

By Lon D. Santis

This paper describes a lightning warning system (LWS) in operation at the U.S. Bureau of Mines' (USBM) Pittsburgh Research Center (PRC) from December, 1989 to April, 1991. An electric field mill measured the DC atmospheric electrostatic field. Also, an economical on-line weather data service provided lightning location maps and other weather information. A system such as this can significantly improve the safety of explosive handling. The use of these two methods addresses the detection of thunderclouds building overhead and the prediction and tracking of developed storms. Warning reliability of the system was very good when data from both sources were considered. Experience showed, however, that use of either system alone would not provide adequate reliability in most situations. Some problems occurred with the field mill and there is some question whether the instrument is compatible with harsh mining environments or could be made portable. Another method ' of measuring electric field based on fiber optics is discussed. This technology may be able to overcome the problems with field mills.

Jan 1, 1993

Lightning Strikes on Vehicles Transporting Explosives The police in one of the countries in which we operate has asked about the consequences of a lightning strike on a vehicle (box van) carrying detonators and explosives. We have assured them that there is not a problem but they require proof of this.

Jan 1, 2011

By Eduardo Lozano, Vilem Petr

This study demonstrates the ability of high-order, shock-capturing methods to simulate detonation wave propagation in right circular cylinders of non-ideal explosives. 2-D axisymmetric, reactive Euler equations were solved for the detonation of the highly non-ideal explosive ammonium nitrate-fuel oil (ANFO) using a simple pressure-dependent rate law and perfect gas equation of state. The fractional step method was applied to the convection and reaction operators using a 2nd-order Strang splitting. The flow solver consisted of a finite difference scheme where the flux is reconstructed by a modified fifth-order weighted essentially non-oscillatory (WENO5-Z) with local characteristic decomposition and local Lax-Friedrichs (LLF) flux splitting. Time integration was performed by a third order total variation diminishing (TVD) Runge-Kutta time discretization method, also known as the strong stability preserving (SSP) method

Jan 1, 2019

By M Scoble, J Szymans

During the past year, the Canadian Centre for Automation and Robotics in Mining (CCARM), McGill University, Montreal, has been involved with INCO Ltd.'s Manitoba Division in investigating the extent and mechanisms of blasthole deviation. Drilling accuracy can well be regarded as perhaps the single greatest "controllable" factor influencing dilution in INCO's open sloping operations. As INCO and other underground mines seek to minimize dilution, while attempting to maximize productivity, issues of drilling accuracy become increasingly significant. It is important therefore, that means exist by which true blasthole trajectories can be determined, so that if needed, modifications to hole loading instructions or redrilling of holes can be ordered, thus avoiding poor blast results.

Jan 1, 1991

By Rowland Jones

This type of quarrying is very much different from that of established quarries in developed countries, demanding somewhat unorthodox techniques to produce the variety of materials required. The demands on the resourcefulness of-the quarrymaster can be very testing, and produces quite a different breed of individual than what is normally met in managerial status in quarries of developed nations.

Jan 1, 1977

By S. Evans, J. Phillips-White, D. Morton

The partnership between Orica and MMG at the Dugald River Zinc mine in Australia has led to the first global field trials and deployment of Orica’s Subtek™ 4D™ (hereafter referred to as 4D) Bulk Systems underground bulk emulsion blasting technology. This technology offers advantages over conventional bulk explosives by extending the range of energy and length of explosive column that can be charged in underground production. 4D gives blast designers energy options between Relative Bulk Strength (RBS) 50 - 150, delivered uniformly along the entire column in most blasthole conditions along with the ability to instantaneously modify the energy within an individual blasthole. During Phases 1 – 3 of the project from October 2022 to January 2023, over 57 tonnes of the 4D Underground emulsion were loaded in 17 stopes. The primary objectives of this phase were to reduce hanging wall dilution and improve stope recovery. While drilling and other parameters remained unchanged, the energy selection was tailored for specific situations, guided by a revision to the site's drill and blast standard. The design used low energy (RBS 50 - 70) in holes adjacent to the hanging wall and high energy (RBS 130 - 150) where stope recovery had historically been challenging, such as at the toes of long downholes. Initial results of the project focused on five stopes selected for their similarity to those used for the baseline data set. Although the 4D data set was small, the post-blast scans indicated favourable results for recovery and dilution. This suggests that selecting and delivering bulk explosive with tailored energy levels can improve stope performance.

Jan 1, 2024