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By Carl R. Peterson, Robert G. Lundquist

The development of a remotely-controlled drill and blast excavation system is desirable both because it is potentially more economical than mechanical tunneling in hard rock and for safety. A serious impediment to such development is the problem of relocating and reentering previously drilled blast holes to place the explosives.

Jan 1, 1983

By Dennis Dobson, Keith M. Henderson

Lone Star Industries, Inc. in Cape Girardeau, Missouri operates an open pit mine to produce limestone for its portland cement manufacturing plant. The present mining method, for safety and legal reasons, requires a set back from the property line, a berm, sloped overburden, and vertical rock walls with catch benches.

Jan 1, 1997

By Thomas Palangio, Lyall Workman, Jack Eloranta, Tom C. Palangio

The fragmentation distribution of the blasted ore is an important descriptor of blasting results. Traditionally it has been hard to measure quantitatively. Developments in image analysis over several years makes it more feasible to measure fragmentation before crushing on a continuous basis. Post crushing, mill feed distributions can also be measured.

Jan 1, 2007

By Thomas H. Kleine, Alan R. Cameron, William W. Forsyth

In general the software required by a blast designer includes tools that graphically present blast designs (surface & underground), can analyze a design or predict its result, and can assess blasting results. As computers develop and computer literacy continues to rise the development of and use of such tools will spread.

Jan 1, 1995

By N. Paley

An engineering project was undertaken at the Cominco Alaska Red Dog Mine to determine the extent that Semi-Autogenous Grinding (SAG) mill throughput could be increased by blasting differently. The Julius Kruttschnitt Mineral Research Center (JKMRC) blast fragmentation, jaw crusher, and SAG mill breakage models were used to relate changes in the blast design to the SAG mill performance. For optimum performance a SAG mill requires a particular size distribution; a number of large rocks to facilitate breakage by impact, as few as possible middle size rocks that become critical size, and the maximum fines which will pass quickly through an open-circuit mill. Physical constraints of drill and charging equipment size limit the extent that pattern geometry can be changed and the powder factor increased to maximize fines. However, JKMRC research had shown that it appeared possible to increase primary breakage by blasting to such an extent that SAG mill throughput could reach a plateau or even begin to decrease. Modeling was carried out on a range of blast pattern geometries and emulsion explosive blends to determine if a plateau existed and at what powder factor it would be reached. It was found that the relationship between powder factor and grinding throughput was nonlinear. Modeling was also used to compare the SAG mill throughput which could be expected from different emulsion explosive blends to determine which blends should be used in dry and wet holes to provide similar fragmentation. For heavy-ANFO mixtures, the highest modeled throughput was at a ratio of 30/70, with ratios on either side indicating lower throughput. For emulsion blends, the highest modeled throughput was at a ratio of 80/20; however, ratios from 80/20 to lOO/O were similar. Crusher product size distributions were obtained from belt cuts early in the analysis to confirm model predictions. At later stages, actual SAG mill throughput was compared to predicted. The economic benetit from the different blast designs was calculated by accounting for the reduction in recovery due to the higher throughput and the additional drilling and blasting costs. Increasing the powder factor by 150% from the 0.29kg/t {0.58lb/st] being used to 0.72kg/t { 1.44lb/st}, the maximum feasible with mine equipment, could provide a sign&ant net benefit of $3OWyr due to the increased concentrate production. However, because the relationship between throughput and recovery is affected by other factors which were not modeled, a more conservative approach was taken. The powder factor was instead increased by 50°h, providing 45% of the gain. This was possible because the relationship between powder factor and grinding throughput was nonlinear.

Jan 1, 2001

By Cathy Aimone-Martin, Frank Achuff

The New Mexico Department of Transportation (NMDOT) and the Federal Highway Administration (FHWA) have let a contract to Sierra Blanca Constructors for a design / build contract along 38 miles US 70 in Lincoln County, New Mexico. The project will improve safety of travel along the corridor and facilitate the adopted economic development goals of the state. Proposed improvements include widening the existing highway from two lanes to four lanes, providing left turn lane options at selected locations, improving access for businesses and residences, aesthetically enhancing retaining walls, improving storm drainage and replacing the existing pavement with a 30 year mechanistic imperialistic perpetual pavement design. The US 70 Hondo Valley highway project is situated in a narrow valley with steep limestone walls, passes along a Scenic Byway and numerous historic ranching communities with structures that date back three centuries. The scope of work included requirements to monitor and mitigate blasting, noise, and vibrations. The contract was very presumptive with regard to blasting design and procedures. These included visual impact mitigation to treat and stabilize slope cuts, the Migratory Bird Treaty Act protecting roosting and nesting birds from airblast, and the protection of historic and cultural features such as acequias, wells, and structures. Public involvement affecting the rock blasting design has come from citizen task forces and committees concerned with highwall aesthetics and preserving the scenic byway and cultural resources. Constraints placed on the blasting program from agencies and the communities are often at odds. For instance, blasting must produce stable yet natural-looking walls to preserve aesthetics. Restrictions have been placed on pre-splitting and smooth-wall blasting yet safe slope are of the highest priority. This paper presents details of the design/build process undertaken by the contractors to conduct blast rock in an environmentally sensitive region. Blast designs consistent with good construction practices and used to comply with the many federal and state highway stipulations are described.

Jan 1, 2004

By K. Hausmann, W. Whelchel

The properties of ethylene Ionomer resins for the inner layer of non-electric shock tubes will be discussed in detail, and opportunities for property enhancement will be pointed out. A stiffness program for prediction of shock tube stiffness, as determined by the stiffness of the individual layers, will be presented and discussed.

Jan 1, 2010

By Peter Moser, Andreas Grasedieck

In modern rock blasting it is becoming more and more important to achieve a certain specified fragmentation. This means that the rock particles formed as a result of the blast should conform to a desired particle size distribution. An important issue with respect to achieve a desired blast result in terms of fragmentation is both the availability of models for the prediction of the characteristic of the particle size distribution of blasted material and the determination of the energy necessary to achieve a certain fragmentation status. Within the research project “Less Fines” funded by the European Union under project reference G1RDCT200000438, the latter has been addressed by the Department of Mining Engineering& Mineral Economics of the University of Leoben. For that purpose fragmentation results from lab scale blast tests have been analyzed and the relationship between the specific charge used for the blasts and the resulting specific surface of the fragmented material has been examined. Linear relationships between the specific charge and the specific surface of the resulting fragmentation were found for various types of rocks to apply over a range of 10 for the powder factor.

Jan 1, 2004

By Robert F. Dexter

This paper discusses the Federal requirements of this regulation for the importation, manufacture, distribution and storage of explosive materials. The interstate or foreign commerce in explosive materials, licensing of manufacturers, importers and dealers, issuance of permits, the conduct of business by licensees and operations of permit tees and the storage of explosive materials.

Jan 1, 1975

By Miles Huntly

This paper will discuss the ideas and actions that led to the development of a Drill Improvement Team at an open cut coal mine in Australia. It will show significant cost savings can be attained by forming a focused Team derived from all the participants that go into drilling a blast hole

Jan 1, 1999

By Francis O. Otuonye

The results of an ongoing study to determine the response of full contact rock bolts to shock waves due to blasting are presented. A time domain systems modeling and analysis technique was used to identify the axial and bending response of the bolt when explosives charges are detonated at close-in distances.

Jan 1, 1993

By M Lemieux, R Mason

The SABREX blast modeling program was introduced to I.O.C.C.'s Carol Lake Iron Ore Project in December 1987. As part of CIL's Technical Services, SABREX was used to implement an optimization program designed to analyze and introduce various grades of MAGNAFRAC at a constant pattern while maintaining acceptable blast results.

Jan 1, 1989

By Robert Martin, Brian W. Stump

As part of a series of seismic experiments designed to improve the understanding of the impact of mining blasts on verifying a Comprehensive Test Ban Treaty, a sixteen station network of three-component seismic sensors were deployed around a large cast shot in the Black Thunder Mine. The seismic stations were placed, where possible, at a range of 2.5 kilometers with a constant inter-station spacing of 22.5 degrees. All of the data were recorded with the seismometers oriented such that the radial component pointed to the middle point of the approximately 2 kilometer long shot. High quality data were recorded at each station. Data were scaled to a range of 2.5 kilometers and the sum of the absolute value of the vertical, radial, and transverse channels computed. These observations were used to construct radiation patterns of the seismic energy propagating from the cast shot. It is obvious that cast shots do not radiate seismic energy isotropically. Most of the vertical motion occurs behind the highwall while radial and transverse components of motion are enhanced in directions parallel to the highwall.

Jan 1, 1997

By Paul Worsey, Randall Franklin

This paper is based on an undergraduate research project undertaken for the explosives emphasis in the UMR mining engineering degree program by the first author. The purpose of the selected research topic was to investigate the impact sensitivity of commercial detonators to determine their relative safety for handling and how much abuse they can take without accidentally firing. A modified BAM tester was used for the investigation. Both electric and non electric detonators were impacted at incremental positions along their length to determine the relative effect of their various components. Repeat impact tests were also conducted to see how a damaged cap would react to repeated abuse. The results indicate that it takes a significant amount of impact energy to initiate commercial detonators. They also indicate that repeated abuse can increase sensitivity. Modern commercial detonators appear to be relatively insensitive to impact (an order of magnitude above RDX in the standard BAM test) and this is mainly due to their construction. This explains why damaged caps with exposed powder are more sensitive. Their measured insensitivity correlates with rough handling not being a major cause of blasting accidents.

Jan 1, 2004

By Park McLure, Paul Kunze

Abandoned underground mine workings have been regularly encountered in open pit mining excavations for many years, for the most part without many serious problems resulting. During the last several years however, some tragic occurrences and near misses have resulted when these old workings were intercepted. This paper will report on the problem as it relates to western open pit mining and will describe several techniques that can be used to identify problem areas before they are reached: Utilization of old maps and engineering data, long hole drilling and probing, and the use of subsurface investigation in the form of ground penetrating radar are the detection methods that will be discussed. The paper will describe some possible actions, once potential problem areas are identified. Drilling and blasting crews are usually exposed to the hazards involved when these situations arise because of their "on the ground" working environment. It is therefore appropriate that some of the best methods of dealing with these hazards once they are identified, seems to involve innovative and creative blast designs. The paper will discuss these approaches and describe an example of this aspect of the solution.

Jan 1, 1993

By Raimo Vuolio

"Over the past 30 years, the Nordic countries have developed similar practices for estimating damage caused by rock blasting vibrations. However, over the last few years the risk of damage has sometimes been estimated by using international values, which have created unnecessary costs, since they are too conservative. This paper gives a proposal for Finnish blast vibration standards and a calculation model for the extent of the zones for building inspection, risk analysis, and vibration measurements. The international conclusion is that particle velocity is the best descriptor for limiting damage potential for structures. Over 900 000 vibration data recordings from 52971 blasts were collected for this paper during 1970-1989. They show that the most practical description is the vertical component of the peak particle velocity. As rock is a nonhomogeneous medium, it is hard to predict the need and scope of risk analyses, building inspection, and vibration measurements. As a large number of blasts were monitored for the recording of the peak particle velocity in several locations in Finland, and the data combined, it is possible to establish safe scaled distances for the calculation of the need and scope of risk analyses, building inspections, and vibration measurements."

Jan 1, 1991

By Julia Creasey, Natalie Hodgson, Claire Ward, Craig Davies, Helen Sarginson

"Emulsion explosive producers are attempting to lower the cost of emulsion production by using lowquality ammonium nitrate in emulsion formulations. Low quality ammonium nitrate contains additivessuch as anti-caking agents and crystal modifiers which contaminate the emulsions causing instability. This presents a need for an effective emulsifier that will maintain emulsion stability under thesechallenging conditions."

Jan 1, 2017

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 John Brulia, Grant ODell

The AIRDEK blasting method has recently been introduced as an overbreak control blasting technique. This paper discusses the use of a modified AIRDEK blasting method for use in open-face blasting to make cap stone riprap (6-20 ton size) at the Clinton Point quarry of New York Trap Rock Corporation, Lone Star Industries.

Jan 1, 1990

By E E. Cloete, R I. McCrindle

Permitted explosives were previously nitroglycerine based and cap sensitive. Due to safety, health and environmental requirements, water-containing explosives, such as watergels and emulsions, were used instead. However, in order for these explosives to perform at their designed level during blasting, a more powerful stimulus than is delivered by detonators on their own is required.

Jan 1, 1999