Search Documents

By Richard J. Mainiero, T S. Bajpayee

The Bureau of Mines, U.S. Department of the Interior, has developed test procedures and criteria for evaluating explosive reactivity of explosive contaminated solid waste substances generated by U.S. Army Ammunition Plants. These substances are produced as explosive-contaminated sludge from waste water treatment plants, residues from the burning of munitions and explosives on open ground, and residues from deactivation furnaces. The characterization of explosive reactivity is a prerequisite for disposal of such waste materials, which may be contaminated with primary explosives, propellants, or pyrotechnic materials. The Bureau has proposed two tests for this purpose. These tests were developed to evaluate the explosive reactivity as defined in Title 40, Code of Federal Regulations, Part 261.23(a)(6) and (7). These are Bureau of Mines Gap and Bureau of Mines Internal Ignition tests, which determine the sensitivity to shock and thermal stimuli, respectively. This paper also includes gap and internal ignition reference data for typical blasting agents, high explosives, propellants, and marginally reactive substances. These reference data were used to establish test criteria. The Bureau has evaluated over 400 samples of contaminated soil, sludge, and burning residues using these two test methods.

Jan 1, 1988

By Brian Stump, D. Craig Pearson

This work quantifies seismic coupling as a function of charge weight for single-fired (simultaneously detonated) explosions observed in the mine and at regional distances. These single-fired explosions are contrasted to standard production shots from the same mine. Production shots include cast blasts to remove overburden and coal shots for fragmentation. The blasts were conducted in a mine in NE Wyoming. The data sets consist of measurements in the mine (100-10,000 m) and at regional distance (360 km) using a seismic array near Pinedale, Wyoming (PDAR). The single-fired explosions ranged in designed size from 5,500 to 50,000 lbs. Peak amplitudes measured at a single element of the regional array are modeled by a power law relation dependent on explosive weight. Scaling constants were determined for each of the dominant regional phases: b(Pn) = 0.84±0.14; b(Pg) = 0.84±0.09; b(Lg) = 0.91±.08. Spectral ratios of observations from different explosions observed at the same station illustrate the frequency dependnce of the source scaling relations. Spectral ratios of in-mine observations are consistent with those of regional data. The observed single-fired ratios are well replicated by Mueller-Murphy source model ratios. The data and model illustrate both the increase in long-period spectral level and the accompanying decrease in source corner frequency with increasing charge weight. The coal and cast blasts that make up the production shots ranged in size from 77,000 to 4,738,230 lbs. The peak amplitude (1-20 Hz) for the largest delay-fired production shot (4,738,230 lbs.) is comparable to that of the largest single-fired explosion (50,000 lbs.). This comparison can be explained in terms of destructive interference between waveforms from individual boreholes introduced by delay firing. Shot specific models of delay firing suggest that peak amplitudes in this same frequency band for the production shots are insensitive to the total amount of explosives in the blast. Peak amplitude data at regional distances supports his modeling result.

Jan 1, 2002

By Baron Fidler, Dave Lilly, Matt Budin

Cumulative sum (CUSUM) statistical process control methods have been used in many industries to monitor quality control results. CUSUM charts are a method to determine when small changes in data indicate a major change in results. E.S. Page at AT&T developed the method in 1954. In many blasting situations, vibration and air blast readings vary slightly from blast to blast. Whether the change is significant or not can be hard to interpret from the raw data. CUSUM charts can assist in determining whether a major change is taking place and when the change began.

Jan 1, 2009

By B. A. Cheeseman, R. Skaggs, C. F. Yen, S. Wolf

Shallow buried explosives pose a significant threat to lightweight vehicles and their onboard personnel. To date, designers of lightweight vehicles are limited in their knowledge of what occurs during the blast. The high intensity, short term loading imparted by the explosion is enormously complex and can be significantly affected by a number of parameters including the size, shape, type, detonation point and depth of burial (DOB) of the explosive and the type, density and water content of the soil. Recent advancements in numerical simulations have enabled the complex blast event to be accurately modeled by coupling Eulerian and Lagrangian analyses: the former is well suited to modeling the blast and while the latter, the structural response. Further validation of the modeling technique is considered in the current paper, which details simulations performed utilizing the coupled Eulerian-Lagrangian analysis to the study the blast output of explosives buried in saturated sand. These experiments varied explosive charge size, its depth of burial, the target stand-off (SO) distance and target plate dimension. The investigation concludes with a discussion of the accuracy of the numerical simulations when compared with the experimental observations.

Jan 1, 2005

By B. K. Rath

The Industrialization of a country depends on its mining activities to a great extent. In mineral production, India has a top rank not only in South Asia, at the global level too. Quantum of mineral production is almost directly proportional to the quantum of explosive production. Mining sector consume more than 80% of country’s explosive production. Due to rapid growth of mining activities in the country, the explosives industry has been developing very fast in terms of quantity, quality and types. , In this paper, India’s post independent chronological date regarding use of explosives, their types, their constraints and a profile of well-known manufacturers has been meticulously presented. A production figure for three years with system analysis has been presented. The paper also deals with present consumption pattern while making a futuristic forecast. In view of the anticipated changes that are to take place in mining industries in near future, the manufacturers of explosives have to pay a vital role. The paper highlights some concrete and valuable suggestions and recommendations. Small scale Companies have to limit their production to Slurry and Emulsion types of Cartridged explosives whereas the large manufacturing units have to concentrate on Bulk explosives, specialized explosives and better initiating systems. The large manufacturing units have also to make all concerted efforts to compete with global market for significant export. The Country for its rapid growth needs basic raw materials like Coal, Iron Ore and Limestone. So, the extraction of these minerals is of prime importance. The more we produce and consume, the more will be Industrialization. The Industrial growth rate has been around 6% during the last few years. As the Industrial growth rate is moderate, there is moderate increase in mineral extraction in the Country. Additional mineral extraction demands additional explosive production (Annexure-1).

Jan 1, 2000

Casting design for bench blasting in surface coal mines is a new focus and a fairly recent success. This study aims at the development of a mathematical model to predict the throw of overburden material based on geological conditions of a bench and charges in blast holes. The procedure, derived on the basis of blasting theories and dynamics of the multiple-particle system, explores the mechanisms of casting rocks into pits. Implementing the model with a computer program is a part of the study. The computer program will supply quantitative data for evaluation. It serves the purposes of verification for the model and, hopefully, field applications.

Jan 1, 1988

By George P. Schivley

When drilling blast holes, with roller cone bits, a phenomenon known as drilling vibration can occur. It is characterized by either axial or lateral modes of periodic motion of the drill pipe; superimposed on the time-average angular motion of the drill pipe provided by the drill rig rotary head and the vertical motion associated with the penetration rate of the tricone bit into the rock being drilled. This periodic motion can be very severe and, if appropriate action is not initiated by the drill rig operator, could lead to structural damage to the drill rig. Ultimately, the occurrence of drilling vibration limits the productivity potential of a rotary drill.

Jan 1, 1997

Prediction of fragmentation in Taconite Mining is an important aid to blasting engineers. A simple theory relates the intensity of radial fracture per unit length to distance from the borehole, from which a power law for mass fraction passing versus size is derived. For the lower end of the size distribution, the equation agrees well with several published examples of fragmentation from sieving of full scale blasts. Large size fragments arise from interaction of fractures from neighboring holes and pre-existing joints. Analysis of two assumptions regarding radial fracture interaction shows that complex fragmentation distributions can arise from the simple mechanisms proposed. Measured fragmentation falls between the two extremes calculated.

Jan 1, 1996

By Blair Jackson, Tjaart Louw

Martha Mine, owned by Newmont Mining, Australia appointed Macmahon Contractors (NZ) Ltd as the mining contractor to drill, blast, and crush and convey ore for processing, followed by construction of a tails dam facility from the waste material. The open pit is located 140km(90miles) south east of Auckland, New Zealand in the middle of the township of Waihi (the main street of the town with a population of 3,500 is 90m from the perimeter of the open pit mine). Mining must proceed at 325,000m3 (of which involves blasting approximately 11,000 holes per month, in order to ensure continued ore supply.

Jan 1, 2003

By Kirk Yeager

All explosive formulations display some sensitivity to heat. A common technique utilized to measure an explosive’s response to thermal stimulation is differential scanning calorimetry (DSC). As DSC analysis is run on quantities of material easily handled in a laboratory setting, and is relatively inexpensive, it tends to be one of the more predominant tools utilized to determine potential thermal hazards of energetic materials. The analysis of energetic materials via DSC provides unique challenges, as both large energy outputs and significant production of gaseous products result from their decompositions. In addition, the unique thermal decomposition characteristics of ammonium nitrate (AN) based materials have also created difficulties in DSC analyses. A wide variety of techniques have been developed to study the decomposition of explosives. Traditionally, sealed glass capillaries were utilized to house samples. Recently, the introduction of specialty cells designed to withstand high pressures has enabled new sampling techniques to be developed. Analyses of explosives with both traditional and “high-pressure” cells will be compared and contrasted. Lessons learned about the application of both techniques towards analyzing thermal hazards such as incompatibilities will be presented. Inconsistencies in the results displayed during analyses of AN-based explosives will be highlighted. Recommendations on the best approach for analyzing the more problematic AN formulations will be given.

Jan 1, 2000

By Alastair Grogon

Proper coupling of a geophone to a monitoring surface is probably the single most important step in accurately recording and measuring ground vibrations from a blast. Over the years, a number of monitoring methodologies have been published. Some of these were published as a "standard", by organizations such as the International Standards Organization, others as suggested methods by various authors in papers or text books, or in the users manuals supplied by seismograph manufacturers. These monitoring standards differ, and are sometimes apparently contradictory. The purpose of this paper is to summarize the coupling methodologies from a number of these "standards", point out similarities and differences, and discuss the technical basis behind some of the different methods.

Jan 1, 1998

By Donald C. Clark

The Blasting Contractor as an Insurance Risk involves a discussion of changing times in the insurance market and changing methods of operation in the construction industry. Since the advent of Internal Revenue Service~1 and Occupational Safety and Health Act~2 regulations by the Federal Government in the early 1970's, operations have changed. Many small users of explosives have discontinued any use in favor of subcontracting the drilling and blasting to specialists. This change in operations along with the change in the insurance market has created coverage problems which is the subject of discussion of this paper. Although no definite conclusions are reached, it is an attempt to promote understanding and further the efforts toward equitable solutions.

Jan 1, 1977

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 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 Byron Groen, Corry Goumans

Description of Project: Project location is at WAC Bennett Dam in Hudson’s Hope, British Columbia, Canada.

Jan 1, 2014

By D T. Froedge

In 1972 the Kentucky State Legislature enacted House Bill 625 which was known as the Kentucky Blasting Law. This law was enacted primarily to stop problems associated with surface mining, but when it was enacted all industries using explosives were included. The bill was assigned to the Department of Mines and Minerals which created a Division of Explosives and Blasting. At that time, this division only had regulations concerning blasting. One should make a distinction between blasting regulations and other explosive regulations. Blasting is the actual use of explosives, the control of the blasting operation, how much is used, at what distances to buildings, the yardage, and other actions associated with the detonating process, explosives regulations generally including safety to the personnel and the storage of explosives.

Jan 1, 1977

By P. D. Lightfoot, C. Badeen, R. Turcotte, D. E. C. Jones

Following localized (i.e. hot-spot) ignition, there is a minimum pressure required for combustion to propagate in water-based commercial explosives. The latter is usually referred to as the ‘Minimum Burning Pressure’ (MBP) of the explosive. In the present work, both an apparatus based on hot-wire ignition and an associated methodology were developed to measure the MBP of water-based explosives. It was demonstrated that the MBP constitutes a sharp pressure threshold below which the probability of inducing sustained burning in these explosives becomes very small. It was found that each emulsion explosive tested has a distinct MBP value, which depends critically on its formulation. It appears that this test may offer a firm basis for the classification of emulsion explosives for regulatory purposes.

Jan 1, 2004

By Pierre Mousset-Jones, Geraint W. Harris, Robert Karlin, Jaak Daemen

In order to minimize the ore dilution induced by blast movement in surface mines it is necessary to quantify such movement. This will make it possible to more accurately locate the grade boundaries on the surface of a blasted rockpile prior to excavation. This paper describes the development and testing of a method to accurately measure the direction and magnitude of sub-surface blast movement. The technique involves the use of magnetic "radiometry, using a cesium vapor "radiometer and real-time differentially corrected, GPS system, to locate the post-blast position of magnetically enhanced target objects, whose pre-blast locations are known, without disturbance of the blasted rock. The objective is to design an accurate and efficient technique which can be integrated into a mines production cycle.

Jan 1, 1997

By Peter P. Harvey

The Nonel Primadet is a non-electric delay blasting cap initiation system. The most recent field application of the system in the Southwest has been at the Magma Superior Mine, Superior, Arizona.

Jan 1, 1978

By C Yeung, G Fitz, R Heater, P D. Katsabanis

Explosives malfunction due to shock waves is a serious concern for successful blasting results. Malfunction can range from sympathetic detonation to desensitization and modification of firing times of conventional pyrotechnic detonators.

Jan 1, 1994