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By Brian Wingfield, Rick Givens, Greg Williams

Many technological advancements have been made in explosive products and applications over the last 15 years resulting in productivity and cost gains. However, the application of total energy (engine horsepower) in the majority of rotary drilling technology, has remained virtually unchanged over that period. While advancements have been made in components, efficiency, and types of hydraulic systems used on drills, the application of current hydraulic technology to improve drilling productivity has not been interactive with end users.

Jan 1, 1996

By Conny Postupack, Jim Petrunyak, John Hope

The authors discuss the concepts, engineering considerations, and cost relationships involved in the use of drilling and blasting to accomplish backfilling and reclamation with minimum use of mechanical equipment. The four xchods o f reclsnacisn now in use are reviewed, and their advantages and disadvanrages a r e nocea. Guidelines for seleccrng a particular method are offered in terms of applicability under varying geologic, economic, and technological condirions.

Jan 1, 1989

By Andrew F. McKown

Overbreak and damage to rock walls at the perimeter of rock excavation can lead to safety problems due to rock falls and additional costs due to a] extra mucking, b] extra concrete or shotcrete to backfill overbreak, c] additional rock reinforcement, d] additional water inflow and e] additional maintenance of rock walls. To minimize these undesirable effects, there are several perimeter control techniques available (i.e. line drilling, cushion blasting, pre-splitting, smooth blasting, and fracture control blasting) which control perimeter hole spacing, burden and loading to provide a smooth, stable excavation contour. Conventional perimeter control loading and hole spacing is satisfactory for massive, homogeneous formations, but when blasting in weathered or fractured rock closer spacing and very light loading is required.

Jan 1, 1984

By Charles L. Greening

MARTIN MARIETTA CEMENT at Martinsburg, West Virginia, has been and presently is engaged in coupling present open pit with old underground workings. Various drilling and blasting techniques have been introduced in an endeavor to achieve optimum results. This paper will relate to three roof shots at Martinsburg, one of which realized a controlled blast of 248,000 tons of material.

Jan 1, 1982

By Joshua Hoffman, Rhys Baker, Tim O’Brien

Numerous agencies in the Executive Branch of the United States Federal Government have regulatory jurisdiction over the explosives industry. These agencies develop the rules by which the explosives industry must operate, and many have the authority to enforce those rules. Likewise, there are entities in the Legislature that have oversight of those agencies and develop the laws that agencies must operate under. These entities in the Legislative Branch are Congressional Committees. Each committee has their respective jurisdictional authority over various agencies and issues. There are several Congressional Committees with jurisdiction over the agencies that govern the explosives industry and they differ slightly between the House of Representatives and the Senate. This paper discusses this division of power as it relates to the explosives industry. Each branch is responsive to the public and the processes through which each promulgates regulation and legislation require public input in different forms. Options for civic involvement for engaging each of these bodies of power in their respective processes are presented. The differences between legislation and regulation are highlighted along with the processes by which each are promulgated. A proper understanding of the governmental mechanics that affect the explosives industry are critical for the industry to be able to be proactive in playing a role in these processes in a democratic way.

By S. Huang, K. Xia

The down-stream size reduction processes such as crushing, grinding and milling, represent major expenditure of energy. The present study is aimed at linking the fragmentation characteristics of the rock feed in a crusher with the physical and mechanical properties of the rock and the energy expended in the process. This is done through a modified Hopkinson Pressure bar apparatus, where both the impact velocity and energy input can be carefully controlled. A single layer of rock particles of very narrow feed size range (9 mm - 12 mm) and occupying a fixed volume in a chamber is impacted by means of a striker. The resulting fragment size distribution is determined for two different rock types (e.g. a granite and a limestone), involving single and multiple impacts, with all other experimental parameters remaining constant. The progressive reduction in overall product size and detailed fragment size distribution curves are obtained through sieve analysis, for specified number of impacts. The resulting fragment size distribution is analyzed in the light two distribution functions, Rosin-Rammler and Swebrec.

Jan 1, 2015

By R R. Singh, U K. Dey, S K. Roy

"Commercial explosives being a heterogeneous mixture of many chemical compounds in prefixed proportion, their velocity of detonation (VOD) may vary from batch to batch, due to variations in the proportion of the chemical composition and process parameters even within their tolerance limits. Inherent limitations of measuring methods and human variations during measurement also add to the variation in VOD values determined practically. Therefore, it is customary to define a range of VOD values rather than a fixed value of VOD for a particular explosive.Variations in VOD values of four commercial permitted explosives in India were evaluated under open unconfined condition using Dautriche method and a resistance wire method based continuous VOD meter. Comparative evaluation of VOD values of selected explosives were aimed to check the relative effectiveness of continuous VOD measurement of small diameter cartridged permitted explosives using cheaper co-axial wire instead of recommended costly VOD rods along with the continuous VOD meter. Results of evaluation revealed that continuous VOD of commercial small diameter cartridged explosives could be determined using cheaper co-axial resistance cable with comparatively better accuracy than the most commonly used Dautriche method."

Jan 1, 2007

Bloomfield Collieries Rix’s Creek Mine is an open cut coal operation located in the Hunter Valley region of Australia. The mine produces approximately 1.1 mt of saleable product per year and routinely employs cast-blasting practices for its unique dragline-truck overburden excavation method.

Jan 1, 2006

By M. L. Mendes, J. Q. Nojiri, S. C. Botelho, A. P. Campanha

In February 28, 2001 JOULE coordinated the first tests with an electronic detonator in South America at an iron ore operation - ITABIRA MINES from the Brazilian COMPANHIA VALE DO RIO DOCE (CVRD) - the largest producer and exporter of iron ore in the world. ITABIRA MINES (CAU and CONCEI O) belong to one of the complexes, called the Southern System, producing 56 million tons of ROM as well as concentrated products and pellets. This paper is going to describe the tests at ITABIRA MINES with results indicating the improvement in the excavator productivity and reduction of the mining global costs (due to the better performance of the equipment and potential reduction of the maintenance cost).

Jan 1, 2002

By Benjamin Cebrian

Metallurgical testing at Cobre Las Cruces prior to production at the mill was done with overburden gossan. Some of that test gossan was a very fine material, wet by the water conditions at the bottom of the pit. When processed and stored wet at the fines material 3000 tonne (3307 tons) silo, this material cemented in a very unusual manner.

Jan 1, 2010

By Walter Voglauer, Elisabeth Zechmeister

Description of Project: The four photos show a chimney blasting operation in Vienna’s district of Floridsdorf on May 4 2011. The blasting was done with two types of charges. An internal charge provided a force of blast which resulted in 135 single electrical blasting caps initiated detonations on the basic ensured the straight collapse of the chimney. The preparation work was done by reserve force military engineers. The series of photos were shot by Elisabeth Zechmeister. She works in the Austrian DOD but not as a professional photographer; much more she did all activities in her spare time.

Jan 1, 2013

By D Maxwell Ellett

This report presents an evaluation of knowledge concerning a process used in predicting ground motion resulting from large scale conventional explosive detonations, The shots were set off in Arizona in connection with copper ore recovery activities.

Jan 1, 1976

By Otto E. Jr Crenwelge, Timothy A. Peterson

We have developed a site-specific method for analysis, prediction, and control of ground vibrations induced by overburden blasting operations in surface coal mines. Field tests conducted at R&F Coal Company have verified our approach for obtaining signatures of the overburden vibration characteristics at locations of interest near the mine, selecting the optimum excitation frequency for minimizing vibrations, measuring and synthesizing multiple-charge excitation signals for minimizing vibration amplitude and duration and controlling frequency, accurately predicting the multiple-charge vibration response in both the time and frequency domains, and accurately controlling the blast detonation to achieve the predicted vibration control. Initial field studies also indicate that by minimizing the vibrational energy radiated from the blast zone, and by optimizing the number of charges detonated per delay period as allowed by this technique, more effective use of the explosive energy is obtained within the blast zone itself for improving overburden fragmentation, swell, and cast. In all of the phases of this technique, including actual blast detonation, personal computer hardware and software have been verified for use in either field or office environments.

Jan 1, 1986

By Robert Hopler

In use, blasting powder is exploded by a spark from fuse, electric squib or miner’s squib, or by a primer of some high explosive, the last being employed only in heavy charges on open work. In mining, and sometimes in light charges on open work, blasting powder is made into cartridges by means of a paper tube or cylinder sealed at one end, which is known as the Du Pont tamping bag. Sometimes the paper cylinder is made by the miner by coiling a section of heavy paper, known as blasting paper, around a wooden pin, called a cartridge pin, and securing it with what is called blasting soap. The removal of the pin leaves a cylindrical cartridge open at one end, into which the powder is poured and the top folded and sealed with blasting soap.

Jan 1, 2014

By Michael Wieland

Smoke/fume measurements from rapid transitory charge reactions are not wholly comparable with thermodynamic reaction code (TDRC) results, since quenched chemical reactions yield nonequilibrium concentrations. Though the work output and major reaction products are usually rendered with minor deviations, the toxic fumes and other minor concentrations reveal some major discrepancies. Work output for charge formulations in underwater or fixture tests were theoretically resolved with work-principal models that form a rough thermodynamic trajectory. Stalled nonequilibrium concentrations are rationalized by finding the underlying quenched reaction(s). The wide relevance of the Zeldovich radical-chain mechanism that transforms nitrogen oxide was previously recognized. The work-principal model (WPM) represents reaction quenching with off-trajectory constraints to render the fumes, without noticeably readjusting the work process. When restraints that characterize the confinement are WPM tractable, the resolution of critical reaction mechanisms is worthwhile, since they remain useful, regardless of the rich, neutral or lean stoichiometry of the charge formulation.

Jan 1, 2012

By Alejandro Rosario, Ricardo González

The restrictions imposed by the Brazilian environmental legislation regarding natural caves lead to a block of substantial amount of mineral reserves. Mining activities can released caves, as long as the company ensures that the activities will not cause any damage to them, requiring profound and time-consuming studies. Since the use of explosives in the mine are potential sources of some damage to any structures, it leads to a deep need for controlling the rock blasting activities. In this context, the maximum charge per delay used in operations close to cave regions must follow some internal blasting assumptions that have been developed during specific tests and mining activities. By the seed wave technique, it is possible to determine the behavior of a seismic wave, which travels through a rock mass and it is generated by blasting a known explosive charge. This technique has proved to be an effective tool because it is able to accurately include the physical characteristics of the rock and different lithologies. This paper discusses about modelling blasting induced vibrations in order to improve caves protection, which surround the mining operations.

Jan 1, 2019

There is an intuitive tendency to equate rock strength with rock stability, yet the two must be evaluated separately. A slope in strong hard rock is not necessarily stable, nor is a slope in weathered weak rock necessarily unstable. In some cases the reverse is true, depending on the geometry of joints and weak planes. The time element is a matter of special concern, that is how suddenly the failure begins and how rapidly it progresses. Sudden failures can be catastrophic, whereas creep usually is not. In soils and weathered rock, the process is usually incremental and is more likely to give some warning of impending failure. With careful observation, the failure process in these materials can be detected and monitored instrumentally or visually. In some cases, the slope may be stabilized, reinforced or modified. When that is not possible, there is usually enough time on this type of slope to remove men and equipment from the area before complete failure occurs.

Jan 1, 1996

By Zoltan Susanszky

Technical development in blasting requires improvement of industrial explosion techniques in two fields. One is to apply increasingly exact and economical solutions with more effective explosives, the other is to restrict as much as possible the environmental effect of explosions.

Jan 1, 1978

By George Young Mosteller

This paper is summary of the practical solutions developed in the excavation of drilled piers (caissons) at GPCo's Plant Scherer, Juliette, GA. Plant Scherer is a 3,245 Megawatt Fossil Fuel Powerhouse and, when completed, will be one of the largest fossil fuel plants in the Southeast.

Jan 1, 1980

By Shazad Hosein, Rob Farnfield, Bill Birch, Liam Bermingham

The propagation of a shock wave through air as a result of quarry blasting consists only of one type of wave, the compression wave. This is in marked contrast to seismic waves where a number of different types of wave are generated by the one blasting event. Even so the interaction of the burn time of a single hole and the resulting air overpressure is still too complicated to be able to be accurately modelled from first principles. It is considered that the best way forward is to monitor an individual single hole to obtain a signature wave form that has resulted from this complex interaction. Once this wave form is known, the variation in geometry of a mutli-hole blast and the timings of the successive detonations can be modelled to give a sufficient degree of accuracy to recreate the likely magnitude, duration and wave form of a multi-hole quarry type blast. This can then be directly compared with actual air overpressure wave forms from quarry blast to verify the model.

Jan 1, 2012