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By Matias Suarez, Diego Zenteno

This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002).

Feb 1, 2020

By Matias Suarez, Diego Zenteno

It is known that the introduction of electronic timing in the sequencing of blasting has changed the vision and way in which mining is developed. It is possible to deal with more complex and sophisticated drilling designs, without compromising productivity or safety. It has been shown in various studies, that a correct timing of the blasting provides an improvement in the improvement of the processes downstream, due to a decrease in the resistance of the resulting fragments coming from the interaction of the waves generated in the detonation of explosive loads. On the other hand, it has also been shown that variations in the composition of a same type of explosive, has a significant influence over the resistance of the blasted material, also the energy associated to break it, affecting directly its degree of fragmentation. This paper is aimed to display the new advancements of blasting engineering done in different mining sites throughout the country, associated to electronic sequencing, energy of the explosive and its impact on the fragmented rock. This document explains how to define and implement selective sequencing in the blasting in order to promote the propagation of cracks, therefore impacting positively the productivity through the use of the LaGrange diagram. The LaGrange diagram is a very convenient and illustrative method to present the dynamic behavior associated with wave and crack propagation (Rossmanith. H, 2002). This study focused on the methodology of the formation and measurement of seismic pulses, through the rock massif. For this purpose, seismic pulses were acquired in the field and then, the different dynamic phases of the wave were molded mathematically, with the purpose of favoring the coupling between them.

By John F. Vynne

This paper will discuss the application of available monitoring technology on blasthole drills with the goal being to reduce costs and increase productivity. Case studies from the monitoring of blasthole drills in North American open pit mines will be used to illustrate the ability to meet these objectives.

Jan 1, 1997

By Michael D. Duffy, Martin W. Chenoweth

"Tenn Luttrell Company (TLC) is a major lime and limestone producer in the eastTennessee area. The property, which isreferred to as the Chesney Mine, has been mined from the surface and underground overthe past 20 years. The ore body consists of three major zones of chemical grade limestonewhich lay at a dip of 30 _ 65 degrees. In July of 1989, Tenn Luttrell Company made thedecision to reopen the underground operations which had been suspended during a time ofincreased surface mining."

Jan 1, 1993

The use of angled shot holes can be extremely effective in blasting faces that either have a great deal of toe burden or where it is difficult to give a drill access to a face due to backbreak and face erosion. However many quarry operators are wary of using angled holes because of the perceived possibility of increased flyrock and uncertainty of the driller's abilities to drill at the designed angle.

Jan 1, 1994

By Randall M. Wheeler

Computer analyses of single hole signatures are often used to help blasting operators predict the type of ground vibration effects that may be produced from production blasts incorporating various delay intervals. Frequency analyses of single hole waveforms and subsequent multi-hole waveform simulations can allow an operator to determine the best type of delay intervals to use in order to minimize low frequency ground vibrations.

Jan 1, 1989

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 Mark Mammele, John Bowles

With the continuing rise in the cost of petroleum products and the focus on the increasing use of renewable resources, a readily available, economical replacement for fuel oil in ANFO is the logical next step, and has finally come to realization. This “green” fuel is plentiful, derived from renewable resources, more cost effective and reduces CO emissions. It also increases product density and bulk strength performance. As this unique fuel replaces some of the mass of ammonium nitrate prill, increased savings will be realized proportionally with the increasing cost of ammonium nitrate. Minimal changes are necessary, as this renewable fuel is designed for use and handling with current, commonly used ANFO blending and loading equipment. This proven technology is now in use by commercial operations in the Southwest, providing significant economic benefit with reduced cost per hundred weight of ANFO consumed.

Jan 1, 2008

By Paul V. Sterk

In the early 1980's, the Homestake Mine converted from labor intensive methods such as open cut-and-fill mining to Vertical Crater Retreat (\/CR) bulk mining and mechanized cut and fill. This transformation occurred as a result of high costs and low productivity associated with open cut-and-fill mining. Use of Vertical Crater Retreat allowed Homestake to contain waste development rock within the mine to further decrease costs since the voids created from VCR stopes provide a good receptacle. The need to access these voids from surrounding development to facilitate waste dumping precipitated the development of drop raising. This system is cheaper than raise boring because it allows drilling into the top of an open stope without the expense of raise boring cutouts or equipment. It's safer than conventional raising since access from the bottom is not required. Two methods of long hole raising or "drop" raising have been successfully developed at the Homestake Mine and can be categorized as Ring Drill Drop Raising using 2-1/4 inch holes and VCR Drop Raising using 6-1/2 inch holes.

Jan 1, 1991

By Dr. Calvin J. Konya, Anthony Konya

Beginning on the Niagara Power Project, presplitting became a widely used blasting technique to obtain smooth walls in mining and construction projects reducing scaling, creating more stable pits, allowing the application of slope steepening to reduce waste removal and increase mining depths, and increasing the safety of mine and construction workers. This technique has been minimally studied in comparison to production blasting and currently two separate theories are present on the mechanics behind the presplit. The first is that shockwave collisions between boreholes cause a tension zone to develop causing the split formation. The second is that gas pressures build in the boreholes causing hoop stresses between holes leading to a presplit formation. Practical blasting methods in presplitting such as propellant presplitting and precision presplitting would not be applicable based on the shockwave theory yet are widely used and documented in the industry. Along with this, modern research using a borehole simulation device and advanced pressure gauges have allowed the authors to obtain true borehole pressures in decoupled blastholes. This paper will present this research which correlates the borehole pressure to variables such as the Young's Modulus and Tensile Strength of various rock types giving blast designers the ability to design a presplit to function in many rock conditions, including weak rocks such as siltstones and mudstones.

By Anthony Konya, Calvin J. Konya

This paper will present this research which correlates the borehole pressure to variables such as the Young's Modulus and Tensile Strength of various rock types giving blast designers the ability to design a presplit to function in many rock conditions, including weak rocks such as siltstones and mudstones.

Feb 1, 2020

By Navid Mojtabai, Jaak J. K Daemen

Some facilities require ground vibration limits that are far below typical vibration levels of interest in most blasting situations. A possibly extreme example of such a facility might be the proposed SSC (Supercollider Super Conductor) high energy particle study system. The applicability of conventional blast vibration predictors for such a low amplitude vibration is highly uncertain. For this preliminary study, a series of field measurements are made, and the results integrated in a set of vibration predictor equations. Ground vibrations induced by blasting operations at one proposed SSC site are monitored at close distances (hundreds of feet), intermediate distances (miles), and long distances (tens of miles) from the blasts. Peak particle velocities are recorded at short distances, ground displacements at other points, as well as frequencies. Theoretical analyses are performed by integrating all data in a variety of ground vibration predictors. From the statistical analysis of the data, ground motions at various points along the ring site are predicted for a given charge weight. The approach taken appears adequate for making tentative estimates of exceedingly low amplitude vibrations at great distances from mine blasts.

Jan 1, 1987

By Gour Sen, Peter Bellairs

Blasting conducted in rock temperatures greater than or equal to 55°C (13 1 “F) and / or in rock containing sulphide minerals and their oxidation products can result in unplanned detonations. Blasting practices involving the identification of the affected areas together with the use of speciality explosive products and rigorous attention to quality control are required to safely blast in these types of environments. Sulphide dust explosions occur in some underground mines where the primary blast results in a secondary explosion of the sulphide rock dust which propagates some distance from the primary blast area. This phenomena results in considerable damage and the generation of significant volumes of toxic gasses delaying re-entry to the affected area of the mine thereby increasing both costs and safety concerns. The exothermic reaction between ammonium nitrate based explosives and rock types containing partially oxidised sulphides have resulted in numerous high risk blasting incidents. These reactions can occur at ambient temperatures and often result in premature detonations / deflagrations causing a great deal of consternation at the affected minesite resulting in lost production and considerable expenditure to solve the problem. Rock masses at elevated temperatures can also result in unplanned detonations unless appropriate precautions are taken. This paper discusses each of these hazards, cites some case studies and details appropriate generic safe and efficient blasting techniques for each of the above applications using appropriately formulated explosive products.

Jan 1, 2000

By Tom Donnelly, Roger C. Ilsley

Remote telecommunications seismographs were used to monitor blast vibrations at two historic structures in Cedarburg, Wisconsin during adjacent sewer line construction. The purpose of the vibration monitoring program at the historic structures was to maintain blast vibrations below limiting tolerances established by the Wisconsin State Historic Society.

Jan 1, 1991

By William Yutmeyer, Meredith Hardwick

Since 1996 there have been at least two teams formed within the U.S. Government to develop a consistent set of risk-based standards to be used to govern safety. The first of these was the Risk and Lethality Commonality Team which developed risk criteria associated with protecting personnel during launches at the national test ranges. The second team titled the Risk-Based Explosives Safety Criteria Team (RBESCT) is the subject of this paper.

Jan 1, 2007

By Ulrich Leiste

If the iron ore loss is 15% in the process of mining, the total iron ore loss in the world will be about 461 million tons, this is equal to the total production of 230 iron ore mines each of which produces 2 million-tons of iron ore per year. Based on a series of blast tests in the Malmberget mine, this paper shows that ore recovery can be markedly increased by improving blasting technology such as choosing a correct primer position and making use of shock wave collision. The paper further suggests that a high ore recovery can not only reduce natural resource loss and mining cost but also prolong the life of a mine. In addition, the paper shows an example of reducing blast-caused rock damage in the roofs and walls of underground drifts (tunnels) by using new blasting methods in the Malmberget mine. Finally, the paper shows how the Malmberget mine has successfully reduced the ground vibrations, without adversely affecting fragmentation and ore recovery in sublevel caving mining.

Jan 1, 2014

By L. L. Oriard

he Metropolitan Water District of Southern California (MWD) supplies water to some 16 million people in a semi-arid region. Most of this water is imported. Some of the supply lines cross over the San Andreas fault, one of the most notorious and active faults in the U.S. There was a serious need for emergency water in case normal supplies should be interrupted. To fill that need, MWD had to find a reservoir site on the west side of the San Andreas fault, west of the mountains. Because of the distinctive nature of the location, it was necessary to construct a huge “bath tub” by building a dam at each end of a valley, requiring some 115 million cubic yards (88 million cu.m) of fill. In effect, two large-scale surface mining operations have been under way simultaneously. The $2.2 billion project is known as the Eastside Reservoir Project. Because of space limitations, this paper will be limited to those topics which are expected to be of primary interest to explosives engineers, principally related to large-scale rock fill production. There is not sufficient space to discuss the many diverse geotechnical questions related to site selection, geological and geophysical field testing, laboratory testing and design considerations. This brief overview may assist those who might be interested in making a tour of the project site following the ISEE conference.

Jan 1, 2000

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 Tony Rorke, Sydney Thabethe

A large overburden blast was carried out at Douglas Colliery, Middelburg Mine Services, close to a national road in South Africa. The road is a busy route between Witbank and Bethal and damage to the road could not be risked. The section of road next to the blast was particularly prone to damage, because it had been mined out on its eastern flank, and the large blast was to take place on its western flank. There were thus three potential damage risks: 1. Fly rock damage to the road surface 2. Vibration damage to the road substrate 3. Damage caused by bulk displacement of the block supporting the road into the void on the mined out side. This paper presents the design and blasting methods used to control the blast and avoid these three risks. Electronic delay detonators were used in multi-decked holes. Signature data were used to determine the blast timing to make sure that delays were used that would provide destructive interference. The timing direction and sequence was decided using wave interference patterns to direct repeated shocks away from the road. The precise detonators and the odelling capability allowed effective control of the blast vibration result. Each hole was charged with two explosive decks separated by a deck of aggregate to limit the charge mass fired per delay and thus limit the reaction forces acting towards the unsupported road. The vibration and blast results are presented in the paper, together with the design that was applied. Details are provided on how the blast was charged and primed. The detonators that were used are described and the timing design is presented.Copyright © 2004 International Society of Explosives Engineers 2004G Volume 1 - Blasting Next to an Unsupported Road Using Electronic Detonators 1 of 13 It is concluded that damage risk to nearby structures can be effectively controlled using electronic delay detonators, provided the appropriate modelling is applied to obtain the most effective delay periods.

Jan 1, 2004

By Christoper J. Hunter, Tony Mansel, Carl Kolada

With a current trend toward Bulk Mining methods utilizing both large diameter uphole and downhole drilling, corresponding loading equipment and technology is required to safely and efficiently load these blastholes. Such is the case at Inco Limited Thompson Mine.

Jan 1, 1990