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By Brett Pielstick, E Emery Gray

"Construction of the new Acosta Bridge in downtown Jacksonville, FL required the removalof an historical center lift span bridge once one_half of the new bridge had been opened totraffic. This paper discusses the potential problems faced with the demolition phase of the projectas observed by the CEI (Construction Engineering Inspection) and the blasting consultants"

Jan 1, 1993

By Richard B. O'Meara

"The demand by a customer to an Explosives supplier to fulfill a specialised productrequirement was met by a level headed decision to try to satisfy that demand. This paperwill describe the fundamental steps required in order to develop and produce a newexplosives device, while under certain resource constraints, such that the needs of thecustomer and the supplier are met safely and effectively."

Jan 1, 1993

By D T. Froedge, Michael J. Nutting

A system consisting of an unlimited number of biaxial geophones that measure peak particle velocity and frequency has been developed and utilized at surface mines, quarries and construction sites. An ability to accurately measure ground vibrations completely surrounding a blast and to construct a vibration topograph has facilitated the study of blast design parameters and geologic factors on the resulting generation and propagation of the vibrations.

Jan 1, 1990

By M-C. Lee, Shomaker, R. Turcotte, B. Short

This research program was undertaken to better understand the factors causing abnormal NOx fumes generation from blasting operations in surface coal mining. More specifically, unusual quantities of nitrogen dioxide and nitric oxide have been observed at several surface coal mines in the Powder River Basin, Wyoming. All these mining operations have several points in common: (i) Blasting is performed using gravity loaded emulsions or emulsion/ANFO blends (ii) Unusual NOx (Oxides of Nitrogen) emissions are observed mostly when blasting is conducted in the overburden as opposed to the coal seam itself (iii) The overburden consists of very weakly consolidated ground strata, providing relatively weak confinement conditions for the explosives, and (iv) Significant ground water is observed.

Jan 1, 2002

By James Ludwiczak

We are coming to an end of an era in Midwest surface coal mining. For many years, large tracts of coal lands were readily available for sale or lease to surface mine operators.

Jan 1, 1980

By Viktor Aranovich, Thomas E. Brown

The Almalyk Integrated Mining and Metallurgical Plant is located near Tashkant in Uzbekistan and is one of the former Soviet Union's largest copper producers. Almalyk consumes about 10,000 metric tonnes of explosives annually and expects this requirement to double by the end of the century as they implement a program to boost mine output.

Jan 1, 1998

By Hung Tran, Qian Liu, Patrick Andrieux, Dave Counter

Blast damage in open stope mining has been an important concern in controlling ore dilution. Severe damage to the surrounding rock mass can result in the caving of waste rock and/or backfill materials, as well as general instability of the ground. The blast damage study conducted at Kidd Mining Division in 1995 was aimed at measuring the damage zone around blastholes and at identifying other factors which influence the damage. An approach and methodology developed mainly by Blastronics, together with Noranda under a project with the Mining Research Directorate, was adopted for this project. The principle was to combine vibration measurement results with borehole camera observations to derive the blast damage criteria at the specific site. The Holmberg-Persson Equation was used for the regression of near-field vibration data. The damage criteria was examined with both borehole camera observation results and rock elastic and mechanical properties. Details of this methodology, including instrumentation, are reviewed in this paper and an implementation case study of the blast damage evaluation is presented.

Jan 1, 1998

By David Siskind, Mark Stagg

Vibrations from Dade County (Miami area) quarry blasting and structure responses were measured at 11 locations between February and April, 2000, and 10 homes were inspected to analyze the characteristics of their cracking and other damages. These results were combined with information collected by the County and other studies done in south Florida for a blasting impact assessment specific to this area. In addition over 40 quarry blasts in the nine-week monitoring period, about 800 measurements were available from previous monitoring in Dade and neighboring Broward counties. An overall worst-case analyses based on the highest individual amplitudes suggested that vibrations in some areas could have been as high as 0.35 in/s. While amplitudes in the study period were below this value, they were found to be relatively high for the distances and charge sizes. Attenuation with distance is less in Dade County than found elsewhere with quarries having to use scaled distances several times higher than similar sites in the north. Consequently, the vibrations are perceptible at very large distances.

Jan 1, 2001

By Jose A. Sanchidrián, Ricardo Castedo, Pablo Segarra, Juan Navarro

A study conducted at a mine site that used traditional field surveying and physical hole spot markings bench marked their combined drill and blast performance. The analysis of the operational expenditure (OPEX) improvement determined there were many measurable cost improvements. A primary factor that most operations have to deal with is over drilling of holes. This alone impacts the cost due to nonproductive labor allocations, excessive explosive costs, increased drill tool costs, increased drilling costs and has an impact on the downstream operation cost such as digging the shot material. Other related investigations also show a downstream impact of poor fragmentation on digging payload tonnes, cycle times, haulage payload tonnes, time to load a truck and the number of passes to load the tuck. The intent of this presentation is to draw attention to aspects of mining we understand but may be missing the big picture effects, such as the ability to reduce the operational expenditures consistently to impact the bottom line. The target audience is across the board from owner operators, drill and blast contractors to blasting contractors. Everyone can benefit from these improvements.

Jan 1, 2019

By Courtney Vallejo, Rafiqul Tarefder

This study examines the effects of small scale airblast experiments on cohesive soils and the resulting ground vibrations and crater geometries. Relationships for ground vibration attenuation with soil depth and distance from the blast source were developed. The study is part of a broader research topic of understanding the vulnerability of earthen embankment dams to blast loading. Many earthen embankment dams in the United States were constructed more than fifty years ago and were not designed to withstand high-stress loading such as blast loading. These structures may be susceptible to failure and it is important to describe the response of the earthen dam during a blast event.

Jan 1, 2013

By D Larson, M Finger

Chemical explosives may become a key element in many of the in situ energy and mineral recovery methods under development. This paper discusses the potential role of explosives in deep rock mining for resource recovery. Several energy and mineral recovery programs described are an outgrowth of the Plowshare Program and Explosives R&D conducted as part of the AEC/ERDA mission at Lawrence Livermore Laboratory. Several important aspects of the use of explosives in deep rock mining are reviewed. First, the status of knowledge of deep rock fracturing to create permeability underground is discussed. Completely contained blasting has not been a widely applied tool used in the mining industry. We conclude that data available on deep rock fracture is minimal and that the mechanisms that control the processes must be understood before technical and economic feasibility can be established. We also discuss the unusual problems in the selection of an explosive or blasting agent for deep rock applications including emphasis on the functioning at depth and safety aspects. Finally, a brief review of similar activities within the U.S. is given.

Jan 1, 1976

By Robert Hopler

INTRODUCTION NOT so very many years ago the farm was about the last place where one would expect to find up-to-date mechanical appliances. Steam, explosives, electricity—the factors which have made the world in general, and America in particular, what it is today— were indispensable for the railroad and the steamboat, the factory and the mine, but the farmer’s work was generally run on a comparatively small scale, and was mostly done by the muscles of men or draft animals. Today, however, the farmer as well as the manufacturer, the contractor and the miner, fully appreciate the value of labor-saving devices. Every up-to date farm, large or small, has modem machinery that tends to reduce the cost of production or to improve farm products.

Jan 1, 2011

By R DeLon Hunsaker

In the past, quarrying and other small operations have not been able to take advantage of the lower cost, convenience and better performance of bulk slurries. However, with the introduction of repumpable emulsion slurries and their ability to be stored in containers as blasting agents, bulk slurries are now available for small operations with small diameter boreholes and are producing excellent results. This same concept is being used successfully in larger underground operations.

Jan 1, 1984

By R Deshaise, B Mbhanty

The importance of controlling density of commercial explosives, and the various means to achieve it are described. m e field conditions responsible for density changes during blasting and their effect on blast results are examined. Understanding of the behaviour of density control ingredients such as gas bubbles, glass and plastic microballoons under pressure, is considered essential to predicting explosives performance. Both static and dynamic pressure effects have been studied for typical donor-receptor cartridge configurations. The amplitude and temporal characteristics of dynamic pressures inside receptor explosives have been studied by means of the underwater test, and guidelines developed to limit density changes due to external pressures.

Jan 1, 1989

By Donald Little, Larry Unger

This paper will give a detailed insight into hard rock, large diameter surface blasting including some practical tips to improve blasting practices. These tips will be non-technical, of the nuts and bolts type, intended to help the man in the boots. The paper will begin with the importance of communication between the engineering department and the blasters. What looks good on the mine development map might not blast very well. Tight inside corners, 90 degree outside corners, too few rows; are a few of these problems.

Jan 1, 2006

By Malcolm Scoble, Yves Lizotte, Ajit Singh

Fragmentation size assessment faces difficult problems, traditionally involving tedious and time consuming procedures. Early work had been directed towards developing empirical methods of predicting rather than measuring fragmentation. More recent development of computer-based image processing techniques which derive size distributions by analysis of photographic or video images are reviewed. These are now being adapted by various workers to fragmentation analysis in mines. Results are presented from experimental work aimed to establish the accuracy and precision of photographic techniques for muckpile assessment. Reference is made to McGill fragmentation studies at surface and underground mines in Canada, relating to experience gained in photographic and image processing techniques. The various factors that affect such techniques as well as their limitations and strengths are discussed.

Jan 1, 1990

By Bin Feng, Xiang Fang, Tao Guo, Fandong Lu

Abstract: Rough set theory (RS) can find useful information from a large number of data and generate decision rules without prior knowledge. Support vector machines (SVM) have good classification performances and good capabilities of fault-tolerance and generalization. To effectively control blasting vibration effect, prediction model of blasting vibration parameters based on rough sets and support vector machines are established. Particle swarm algorithm (PS) is used to dynamically discretize attributes. Then, according to the optimal particle calculated by the PS algorithm, the decision table is established. After eliminating less importance attributes and data, then SVM is trained and established for prediction. The model can deal with both quantitative and qualitative factors such as aperture and cast direction, and analyze their importance to peak vibration acceleration value. The improvement of prediction accuracy is verified by testing data.

Jan 1, 2014

By Dale S. Preece, Stephen H. Chung

"In bench blasting, the distribution of loaded explosives with respect to the burden rock has strong effects on digging especially at the toe area. Blast design often focuses on other results such as percent-cast or fragmentation, sometimes leaving a diggability problem at the toe of the blast that is not discovered until excavation. A method for assessing the influence of blast design on diggability has been developed. This method relates the kinetic energy and rock displacement experienced by the material in the muckpile to its diggability. Simulation of the blast along with the calculation of kinetic energy and diggability is done with the discrete element computer program DMC_BLAST(DMC: Distinct Motion Code)."

Jan 1, 1999

By Jim Davis, Calvin J. Konya

The methods used to confine the gases within a borehole can influence the amount of useful energy obtained from the explosive charge. Improper confinement not only wastes energy and raises cost but also can result in airblast, excessive ground vibration, flyrock and boulders. The type of stemming material and amount of stemming used will definitely influence the degree of confinement and the efficiency of the blast. In order to extract the maximum energy from the expanding gases, the stemming plug should never blow out and allow the gases to escape prematurely.

Jan 1, 1978

By Bengt Niklasson

"A test stope at the Luossavaara Research Mine in Kiruna, Sweden,was divided into four different modules in which various hole patterns and explosives were tested in order to evaluate:1. The optimum combination of explosive and hole pattern2. The resulting fragmentation3. The damage to the surrounding rock4. The application techniques of the VCR mining method"

Jan 1, 1985