Search Documents

By Travis Watts, Chris Prater, G. T. Lineberry

Moving overburden at minimal cost is becoming increasingly important to coal mining companies throughout the U.S. The coal market is currently doing well, with an average spot coal price for Central Appalachia product (12,500 Btu, 1.2 SO2) standing at $62.00 for the week ending November 11, 2005, so it is at this time that companies stand to achieve healthy rates of return on their investments. Cast blasting is one method of blasting used effectively by some surface mining operations. This method allows most of the overburden to be removed and placed (cast) directly in the spoil pile by the use of explosive energy. With the proper design of a cast blast, a high percentage of overburden material can be directed into piles without the use of earthmoving equipment, hence increasing production and lowering the cost associated with overburden removal.

Jan 1, 2006

By Carlos Agreda

"In the present article a case study of ammonium nitrate in mine water is briefly analized and discussed. Causes of mine water pollution from AN are very well identified and emphasized.Some preventative measures, as well as, some methods of monitoring and control to minimize, mitigate and/or avoid mine water pollution are recommended."

Jan 1, 1999

By D Reid Watson

A unique blend of theory and hands-on teaching of blast hole drilling and explosives technology is being provided at a Canadian Community College. Students graduate at an apprentice level quite capable of operating and maintaining blast hole drills and designing and executing surface blasts.

Jan 1, 1987

By Tom Short

The contract to drive twin 4,100 foot (1250.5m) long tunnels under the existing Cumberland Gap highway was awarded to a Joint Venture of S.A. Healy of Chicago, Illinois and Lodigiani USA of Fairfax, Virginia in January of 1991 under a $51.8 million bid. Due to very complex geological conditions, there were six distinct categories of excavation, the New Austrian Method of ground support was utilized throughout.

Jan 1, 1993

By He Guangyi, Han Zhilong

This paper introduces the new technology of deep-hole blasting with water-soil mixed stemming to exposed stonework. Nine aspects of advantages are drawn in the paper based on tests of different types of charge and stemming under the conditions of different geology, height of bench and diameter of drill.

Jan 1, 1998

By Richard D. Love

Competition in the aggregate industry of the 90's will be an over increasing really. With this in mind a quarry manager should always be comparing new and innovative concepts to increase productivity and reduce operating costs. In this paper, the author will present a comprehensive history of a drilling and blasting program that achieves these results. By employing proven methods and implementing new concepts, this program was proven to be a success over a ten year period.

Jan 1, 1991

By Kamal Wadhwa

Liquid oxygen explosives have been used in India for well over 5 decades now. These are being extensively used both for shallow and deep hole blasting in the various opencast mines and quarries for mining of coal, limestone, ironore, bauxite, magnesite etc. IOL Ltd., are the pioneers in the introduction of these explosives in India and are marketing these under the brand name 'LOXITE'.

Jan 1, 1991

By Neil E. Gehrig

The word "slurry" was used by Dr. Melvin Cook and Mr. Henry Farnam to describe a new blasting agent developed in 1956. This development, along with the development of ANFO triggered the Modern Era of Blasting. We have seen the results, a massive expansion in the commercial explosives industry. Someone once said, "You can't know where you're going if you don't know where you've been." With that in mind, this paper deals to some extent with the origin and development of slurry explosives and then with their future high potential.

Jan 1, 1982

This paper describes experience in designing and implementing casting blasts over the past fifteen years. Important design parameters such as powder factor, burden and spacing, blast pattern geometry, front row burden and toe distance, pit width versus height, blast length, explosive selection, millisecond delay timing and tie-in types are discussed.

Jan 1, 1995

By Quian Liu

The problem of cross-hole explosive malfunctioning in rock blasting (including sympathetic detonation, desensitization and cut-offs) is a function of delay and spacing in a blast which should be designed to avoid such occurrences. On a delay-spacing chart, the phenomenon of explosive malfunctioning is explained by dividing the chart into different regions, while the shape and size of each region could vary from one explosive to the other. Over seventy blasts have been carried out at the CANMET Experimental Mine to identify the malfunctioning characteristics of specific emulsion, water-gel and dynamite explosives. In each experiment, two parallel blastholes, 32 mm in diameter and 1.7 m deep, were drilled downwards in an underground drift.

Jan 1, 1994

By Max Pena Woolcott, Winfried Rosenstock, Maria Chappuis, Walther Hennig

"In a Peruvian-German Technical Cooperation project for the Mining Sector the ""Milpo-cut"" along with the electric initiation system has been successfully implemented in a Peruvian metal-ore mine.Specific savings in drill work and explosives consumption up to 50 % have been achieved in headings and slopes. The positive results have motivated further Peruvian mining companies to introduce the new technique."

Jan 1, 1994

By Detlef Sulzer, Winfried Rosenstock

"At the end of this century a great breakthrough in the field of blasting technology is finally going tobecome reality. That, in the true sense of the word, is the long expected and desired “HighTechnology Blasting”. So far trials have been carried out in Australia, Africa and Europe with remarkable results, that have been predicted by the authors. As a result, significant reductions of explosives and drilling expenditure are emerging for the future."

Jan 1, 1999

By Bradley C. Paul

Similar rock formations exhibit great variability in resistance to fragmentation during crater blasting. This observation was made during an attempt to calibrate the Kuz-Ram blast fragmentation model for crater blast geometries used in a modified in situ mining method for copper. The KuzRam equation is used to predict the fragment size distribution from blasting and includes a term called the "rock factor" to account for the fragmentation characteristics of the material. A data base of field scale crater shots in oil shale was available to supplement more limited data on copper ores. First, the blast geometry terms of the Kuz-Ram formula were modified to fit field data with various crater blast geometries. Rock factors were chosen to center the predicted curve on the curve representing observed fragmentation. Next, five possible sources of variability in rock factor were investigated: the grade of the oil shale, the aspect ratio of the charge, the type of explosive, the charge depth, and the rock itself.

Jan 1, 1989

By Quian Liu

Since the establishment of the CANMET Experimental Mine in Val d'Or, Quebec in 1991, research activities in rock fragmentation have been carried out not only in the underground laboratory but also in production mines in the north-west Quebec region. Among the instruments available for rock fragmentation, the Kodak EktaPro 1000 Motion Analyzer (also called the high speed video system) has been one of the most useful tools for monitoring blasts in both underground and open pit. This system is capable of recording events at rates from 50 to 12,000 frames per second (fps). The buffer memory has a capacity of storing 2050 images. To use this system in the underground, a steel box was made with a bullet-proof glass in the front to protect the camera. The processing and recording equipment are placed in an aluminum case which can be located about 30 m away from the camera via an extension cable. For each blast monitored, high frequency geophones and accelerometers were used to monitor ground vibrations and give a timing reference of the explosive detonations to correlate with the observation of the captured images.

Jan 1, 1994

By Clive-Workman Davies, K K. Kabongo, Mensah Frimpong

Given the capital intensity of the dragline operation coupled with rising cost of explosives, the onus is on mine operators to make maximum use of explosives in blasting to assist dragline diggability. At a surface coal mine in South Africa large boulders necessitating secondary breakage and in some cases completely unfragmented sections of a blast resulting in low dragline diggability were encountered in the interburden blast. Twelve blasts were therefore closely monitored and dragline productivity evaluated. The ultimate aim was to improve the overall blasting performance and hence increase dragline productivity. Three areas were in focus; fragmentation assessment, dragline productivity assessment and cost analysis. The studies indicated unsatisfactory explosive and initiation performance, problematic blast design and questionable operators performance. It is established that dragline cost account for 60% of the total mining cost whereas the drilling and blasting cost account for the remaining 40% and that improvement in dragline productivity results in automatic cost saving.

Jan 1, 1996

By Zhang Yangde

"This paper reports the clinical research work of Micro-explosion of Biliary Calculi . In theprogram the technique of directional micro explosion applied to disintegrate the biliarycalculi of body and decreases the rate of operation. Up to the present, 235 cases of biliaryduct calculi have been successfully treated by use of implusive force of micro-explosion .The success rate of blasting stones was 100% by the use of the directionalmicro-explosive instrument made by us , the once success ratio of micro-explosion was93.2% and tl~o rmulb of treatment were satisfactory. . Considering the density of theblood vesselsiD the human liver, limitation of space in the h~patic.ducb, the securiey andadaptation, we have designed two types of micro- explosives equipment called ZS device,electric initiation and nonelectric initiation to initiate explosion. The head diameter of thedevice ie 1.5-1.8 mm . It is applicable to all kinds of fiber endoscope by inserting ZSdevice under grossing eyes or TV set ."

Jan 1, 1993

By Claude Cunningham

Simple bulk energy rating of explosives obscures the realities of how these deliver their energy, and diverts attention from the key question of controlling blasting results. Explosive performance is directly related to the pressure pulse impacting on the blasthole wall. This is helpfully visualised by comparing the adiabatic expansion plots for explosives of interest on the right scales and axes. The simple comparison of a pure emulsion with pure ANFO illustrates the practical significance of the intrinsic behaviour of these opposed formulations, showing that the emulsion can be expected to work more by softening rock, while ANFO will tend more to crack it. The explanation for these differences lies in the high shock, low sustained pressure of the former relative to the latter. The technique is readily applied, if a good detonation code is available and able to swap data into a spreadsheet. Any differences between codes will emerge most strongly in comparing the gamma plots.

Jan 1, 2002

By Robert Lee, Jay Rodgers, Kirk Whitaker

The time domain during which an explosive detonates and causes rock to fragment and displace is on the order of tens of milliseconds. Because of this, the dynamic processes that occur during this time frame often become a source of confusion when trying to analyze the performance of explosive products in decked blast designs. As an illustration, the authors have experimentally examined explosives malfunction in decked blasts through state-of-the-art measurement techniques. The interaction of explosive products and blast geometry was examined in detail using the analysis of a series of decked blastholes. Explosive and initiator malfunction in decked blasts is often considered to be entirely the result of insufficient inert decking material, however, it is shown that rock properties and dynamic burden conditions may have a significant impact on decking performance. The successful application of deck-blasting technique for control of ground vibration amplitude relies on an understanding of the true dynamic performance of the blasthole.

Jan 1, 2000

By Andre Pienaar, Larry Wilson, Clive Dawkins

The development of implementation of cost effective emulsion explosive and portable pumping system for the replacement of package explosives in the deep level gold mining environment. A number of versions of portable pumps will be presented, demonstrating continuous improvement on these systems. Data on reliability of units in the field will be presented.

Jan 1, 2009

By Frederick R. Cosgrave

Blasting near buried Natural Gas pipelines has always been an area of great concern. Given the many variables that the blaster must contend with in determining how to break the rock while trying to keep the vibration low and doing so while not compromising the pipeline.

Jan 1, 1995