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By Mansour Asri, Philippe Somogy, Youssef Daffi, Amor Karim

Very few cases of Cast Blasting use in phosphate mining are reported. However, in open-cast coal mining, Cast Blasting is a common practice. And yet, the geological structure of both types of deposits is similar. Accordingly, advantages for phosphate open-cast mines are manifest, especially as future conditions of phosphate deposits fit quite well with the approach.

Jan 1, 2015

By Scott Rosenthal, Kyle Murphy

This paper discusses the trials and tribulations of obtaining Velocity of Detonation (VOD) readings in small diameter blast holes in an underground mine. Montana Technological University (Montana Tech) obtained a time-domain reflectometer (TDR) type VOD monitoring unit. Purchase of the VOD monitor was justified on verifying explosives performance used in Montana Tech’s practical underground mining class and provide a teaching aid for the school’s rock fragmentation class. Before demonstrating the unit to students, we figured we better learn how to use it first so we give the students an appropriate experience. Our first learning was in obtaining the correct coaxial cable for the VOD monitor and how to properly terminate the cable. Once the cable was on-site and terminated, VOD testing could commence. Use of the VOD monitor was tested underground in small diameter holes (1.5-inch, 38 millimeter) pneumatically loaded with ANFO. After a few failed trials, and follow-up discussions with the supplier, VOD readings were obtained for the ANFO loaded holes. Additional readings were obtained for a pre-split product and detonating cord to satisfy our curiosity that the unit was performing as specified by the manufacturer. This paper will share our learnings in the hopes that others can benefit.

By Kyle Wagner, William Joa, Colter Angell, Catherine Johnson, Marty Langenderfer, David Doucet

The goal of any business is to seek the maximum profitability for the organization through optimization the use of resources, processes and the application of new technologies. An analysis of various case studies demonstrate that blasting can have positive impacts on the crushing and milling processes resulting in increased profitability for the mining industry (Grundstrom, Kanchibotla, Jankovich & Thornton, 2001). This paper describes the case study of two copper mines in Peru producing Cu-Mo and Cu-Au concentrates, which together with their strategic partner, have implemented a project focused on the improvement of rock fragmentation. The project was based on techniques of pattern size reduction, the use of high energy explosives and the technology of electronic initiation. Combined, these techniques were shown to have significantly impacted the efficiency of downstream processes.

Jan 1, 2019

By P D. Katsabanis

According to Persson(1) steady state detonation along a cylindrical charge can be regarded as a self propagating process in which the axial compressive effect of the shock front discontinuity changes the state of the explosive so that exothermic reaction sets in with the requisite velocity.

Jan 1, 1990

By Tom Treleaven

The widening of the Panama Canal to approximately 130 feet (40 m) for its entire length began just a few years ago. The original expansion program was slated for completion in 18 to 20 years, but has recently been reduced for completion within the next four years. This means that a tremendous amount of blasting at simultaneous points along the canal, by both the Panama Canal Commission (PCC) and many subcontractors, is necessary to achieve the new completion deadline. The accelerated program also imposed many logistical concerns, since marine trafIic is always heavy and cannot be stopped for blasting. Because some of the large and heavy cargo vessels clear the bottom of the canal by only about 6 feet ( 2 m), the blasting cannot result in any large boulders into the center of the canal, for fear of grounding and damaging a vessel, not to mention the traffic delays and lost income of approximately 1 to 2 million dollars per day.

Jan 1, 1997

By Z X. Zhang

Ground vibrations from the blasts of the LKAB mine at the Malmberget town had reached 18-19 mm/s from year 2000 to 2002. From 2004 to 2010 the maximum vibrations had been reduced to 9 mm/s and most vibrations lowered to about 5 mm/s, indicating that the technical measures used in the mine are effective in vibration control. The major measure that has always been used in Malmberget mine is the method called Changing Initiation Sequence (CIS in short). Another method named Dividing Ring Blasting (DRB in short) is often applied to some special blast rings in the mine. Both methods have been proved to be successful in vibration reduction, and they do not need any additional costs. Because of the two methods, both maximum vibrations and average ones have been reduced by around 50% since 2004.

Jan 1, 2012

By Gary Eck, Kevin Tallent

Over the past decades, the science of energetic materials has advanced dramatically in both the fields of military munitions, as well as industrial explosives. Out of necessity, test methods to measure the explosive performance properties of these materials were developed. As would be expected, these test methods have evolved and become more sophisticated with the recent advancements in electronics and computerized technologies.

Jan 1, 1998

By Felix Torres

CVRD is one of the largest mining companies in the world. Adoption of new technology and improving operational efficiency are top company priorities. Initiatives in these areas have driven continuous company growth and an increased share price. During the first half of 2001, the company had a net profit of nearly US$ 500 M.

Jan 1, 2003

By B Mohanty, G Yamin

A number of parameters, aside from blast design and pre-existing rock conditions, can change the performance of the explosives system in actual blasting practice. Sympathetic pressures caused by detonation of preceding holes have been identified as a major contributor to explosive system malfunctions, leading to uneven blasting performance. These effects can occur both within a hole or across several holes. These can consist of high transient pressures related to the shock phase of the explosion or the relatively longer or quasi-static pressures associated with the explosion gas expansion phase. This study presents the findings from an on- going investigation on measurement and analysis of these pressures between donor and receptor holes in a granitic outcrop for representative inter-hole distances and borehole conditions, employing single cartridges of emulsion explosive in 45 mm diameter holes. The results, despite wide scatter in the measured values, show the very short duration pressures to range up to 7 MPa and arriving within a few milliseconds after detonation, whereas the much lower amplitude pressures arrive after tens of milliseconds. Both have the potential to seriously affect the performance of an explosives system.

Jan 1, 2005

To meet the energy requirements, hydroelectric projects are planned and executed in many countries. Though these projects requires a high capital investment, the returns are regular with minimum maintenance after commissioning of the project and are ecofriendly. Bhutan is situated in the eastern Himalayas and covers an area of 38,394km2 (14824.01sq. miles. It is bordered by India in East, South and West and by Tibet in the North. The hydropower potential of the country is estimated at 30,000MW, out of which around 5% has been harnessed.

Jan 1, 2016

By Phillip R. Mulligan, Kevin Gantz, Aaron J. Ward, allen shirley, Sean Treadway

Understanding the impulse transferred into a structure by the coupled two-phase loading produced by an explosive charge buried in soil is of interest for various applications. The most common impulse measurement technique involves a buried explosive charge and a steel plate/test structure suspended above the charge. Upon detonation of the charge, the soil and overpressure heave the plate into the air. The plate’s trajectory and velocity provide the necessary information to calculate the total impulse transferred from the charge configuration.

Jan 1, 2016

By Luis Valentim, Terry Cousins

The goal of a mine is to produce ore at the lowest possible cost with due regard to safety of pemonnel and equipment. The mining process consists of a number of discrete operations such as planning, drilling, blasting,excavation, transportation and crushing. These processes are interrelated and cannot be considered as separate activities when optimising output and minimising cost. In order to optimise the global costs it may therefore be necessary to increase cost in one area such as blasting design and management beyond the norm.

Jan 1, 1998

By Conny Postupack

The first principle one usually learns about blasting is that competence in this field is best gained by experience in making blasts rather than by reading a book or by listening to a lecture. The reason for this is that there are a large number of variables affecting blasting results and not all of these can be accounted for by a few rules or a few sets of equations. Even an experienced in a new area, may have co make one or two himself to the new conditions with which he blaster when operating shots just to acclimate is faced.

Jan 1, 1991

By R J. Johnson

The development of "SANFO" has provided the Mining Industry with a LOW COST HIGH GAS VOLUME, VARIABLE DENSITY, Blasting Agent which can be blended "On Site" in a simple Agitator mixing and charging system by mine site employees.

Jan 1, 1996

By Charles Deacon

The mining industry is constantly taking greater cognisance of their operating costs as a strategy to counter the effects of falling commodity prices. As a result, optimal operating efficiency is more important than ever. One such operation is that of blasting. Considering the relative increasing costs of explosives and accessories it is desirable to optimise the number of blast-holes fired by maximising their individual output. This achievement may now only be possible following the advent of higher technologies in the form of modified explosives and electronic detonators. This paper reviews and introduces some techniques of blast monitoring, types of operations where each is most suited, resulting modifications to blast designs, and identifies some pitfalls to watch out for when analysing the results.

Jan 1, 2000

By H Ulrich Leiste, Leslie Talor

This paper describes a series of small scale tests conducted to investigate the loading applied to a flat plate by the detonation of a cylindrical charge very close (between two and three charge radii from the center of the charge) to the structure. The testing used very small quantities of explosive (PETN): Two different series of tests were conducted. In the first test series, impulse loading on the target plate was investigated using three different sizes of charge. In the second series, pressure time profiles were determined. The charge size was 6 g or less. Impulse was found using high speed video of the target plate to determine its displacement as a function of time, from which initial plate velocity was obtained. Kolsky Bars, placed at the same distance from the charge as the target plate, were used to determine the free-field pressure time profile of the output of the charge at this distance. Two different types of target plates were used in the impulse study. One was just a plate while the other was a plate constrained with a steel frame.

Jan 1, 2009

By Tom Treleaven, Andrew Williams

Several contracts were let in Greenwich, Connecticut, for the installation of a sanitary sewer. The majority of the excavation was in rock and involved numerous challenges due to the following conditions:

Jan 1, 2003

By William Stewart

Recitations were taking place in the red schoolhouse at Orneville, Maine. It was winter and the snow lay deep on the ground, but some of the scholars were in bare feet, and only half as many hats hung on the pegs as there were potential wearers in the seats. That was forty years ago; and the pioneers of northern New England were more noted for their industry than for their possession of the fruits of it.

Jan 1, 2007

By Kristen Dunlap

There are several thousand remote stream crossing structures in the Tongass National Forest in need of removal. In 2007 thirty-three collapsing log bridges, log culverts, and metal culverts no longer in use were removed with explosives. Species of salmon, trout, char, and sculpin are present in the project area. Blasting overpressures may injure or kill fish in streams and ground vibrations can damage salmonid embryos in streambeds. Regulatory agencies offer guidelines with limits for blasting induced overpressures and vibrations. However, there has been no quantification of blast overpressures in shallow streams. Methods used to predict lethal levels for various blasting applications have not been completely validated. This research provides guidance for analyzing ground vibrations and water overpressures during blasting activities in or around fish streams.

Jan 1, 2009

By Reinhold Schnell, Piers Wendlandt, Nathan Rouse

Drilling and blasting are key components of every hard-rock (i.e.,metal/nonmetal/coal) mining operation. Well-executed and maintained drilling and blasting can have a major positive impact on the overall success of such operations. This case study presents the implementation of a new drill and blast engineer position and systematic improvement of the drill and blast operations at a surface metal mine. The findings of and lessons learned from this case study can be applied toother mine operations to improve safety, production, efficiency, and cost savings. Focus areas for the project included refined communications, operational practices and procedures, planning, designing, and data collection and analysis. This case study showed improved efficiency in communication and planning among the engineers, operations team, and contractor groups over the course of the project. An increased awareness of long-term plans and needs for the drills and blasters reduced or eliminated existing delays. Test blasts that implemented new drill and blast designs and updated operational practices and procedures were tested to streamline the process. Constraints regarding explosive product shipments, geological considerations, and a uniform powder factor provided the basis for new blast designs.