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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 Anne Charline Sauvage

Blast designers and blasters need to know the rock mass influence on blast to increase explosive effi-ciency and to optimize costs, but also to succeed in limiting blast emissions (vibration, overpressure, flyrock) This paper presents an applied approach which makes it possible to structure the information con-cerning the rock mass and the blasting.

Jan 1, 2013

By Cam Thomas

"Reflectorless laser survey equipment has made it much easier to take accurate measurements toinaccessible locations in quarries, open pit mines and rock slopes. Prior to the introduction of thereflectorless laser as a working tool, it was not possible to directly measure to inaccessible locations on rock faces. If a person could not occupy the point, only indirect measurements could be made. For blasting work, measuring the burden in front of the first row of holes could only be done approximately, using such techniques as holding a plumb line in over the crest, triangulating in on a few points or “eyeballing” the burden. This led to direct and significant problems with blasting, including flyrock and airblast (caused by insufficient front row burden), excessive vibrations, problems with oversize and tight digging (all of which may be caused by excessive front row burdens)."

Jan 1, 1999

By Jerry W. Schweiker

An extensive computer program has been developed which will store and analyze pertinent blast related parameters such as date, time, shot coordinates, charge, delay times, etc. In conjunction with these blast parameters, measured ground vibration information can be stored. In addition to actual seismograph data, predicted ground vibration in terms of velocity (inches/sec) can be generated for selected receiver locations. The magnitude of the blast generated ground vibration is based on scale distance relationships. The program can be used for planning blasts, to satisfy local environmental regulations and for insurance and/or legal purposes.

Jan 1, 1984

By B J. Kennedy, G W. Sengstock

During the last two decades, many advances have been made in open cut coal mining technology as new mines have come on stream and old mines have faced increasingly difficult mining and operational conditions. The need for close control of operating costs has necessitated consideration of modified excavation methods.

Jan 1, 1995

By Michael Swisdak, John Tatom

In a quantitative risk assessment (QRA), the ability to accurately model real-world situations is obviously critical. In the end, the model must be able to represent the effects produced by the detonation of the donor and the consequences on the target. The science that goes into such a model must be carefully thought-out and based on as much data as possible.

Jan 1, 2007

By J R. Phin

The properties of all available modern blasting initiation techniques are reviewed. Primadets are nonelectric initiators, the nonelectric features of the system eliminates concern of premature initiation from static or stray currents. The loading techniques are simple and a minimum of training is required. There is no limitation in the number of necessary sequences in which the Primadet need be connected for initiation. This flexibility improves vibration control,and often reduces costs due to increased fragmentation.

Jan 1, 1975

By Theodore C. Hile, Floyd P. Henry, Ken Gragg

"Conventional explosive-storage methods usually rely on combinations of earth and concrete barriers, along with sufficient distance between limited explosive loads, to avoid accidental conflagration. However, under many circumstances, Air National Guard (ANG) facilities co-located with civilian airfields have trouble meeting necessary Quantity-Distance (Q-D) requirements for Explosive Hazard Class/Division 1.1 and 1.4 materials. Because of the danger posed by explosives stored in earthcovered magazines (ECMs) too close to civilian activities, ANG units often find itdifftcult to maintain adequate stores of ordnance needed to meet unit mission goals."

Jan 1, 1999

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 Dale Preece, Stephen Chung

The DMC-BLAST (Distinct Motion Code) has been developed for modeling bench blasting to one or two free faces such as choked blasting in surface gold operation and cast blasting in coal mining, respectively. This computer code has been used to assist the analysis of rock mass displacement after a blast was initiated in an orderly delay sequence. Applications of this feature can be found in the studies of dilution control in surface mining of gold as well as coal involving complex rock structures. Recently, DMC-BLAST has been modified to include a designated delay firing order coupled with variable rock strengths in the blasted media. This newly added feature allows the investigation of the effects of delay firing order on rock displacement in blasting a complex interbedded ore-waste structure. Examples of blasting a steeply dipping coal seams and bedded rock structure, especially in coal mining operations will be addressed and the comparison of efficiency in blasting in an up-dip as opposed to blasting in a down-dip direction will be discussed. Also covered in the paper is a new application of DMC-Blast to simulate a stope blasting underground. Simulations of blasting in a few selected types of timing/structure combinations will be presented in this paper.

Jan 1, 2000

By W. Reisz

Dealing with misfires can be one of the most difficult and serious issues that blasters must confront. Most of us will - at some point, have to deal with a misfire situation.

Jan 1, 2009

By Tristan Worsey, John Henchion, Nathan Rouse, Yannick Lauras

"This paper presents an approach used to plan and evaluate drill and blast trials for a mine that currently mechanically excavates in-situ rock. The document presents the approach used to plan the trials, the key performance indicators (KPIs) that were necessary to evaluate the mining methods, the test matrix used during the trials, and the results of the trials. The trials, which occurred as part of an overall drill to mill optimization project at this site, helped to evaluate various blast designs using fragmentation results,drilling and blasting costs, and downstream costs. This project was unique in that (1) drill and blast methods were trialed on multiple rock types and various bench heights using a range of blasthole diameters and powder factors and (2) the load and haul costs were evaluated using a range of loading equipment, from 66 tonne (73 ton) excavators up to 250 tonne (276 ton) excavators. A ten year net cost financial evaluation of the material extraction alternatives was also prepared for the site management. Ultimately, the process of evaluating the drill and blast trials helped the management decide whether to continue extracting using mechanical methods or to introduce drill and blast methods to extract the rock."

Jan 1, 2017

By Alan Tordoir, Mark Roberts

The drill and blast process is a critical function within the production cycle which significantly impacts the ability of an operation to effectively meet its safety and production targets. Acknowledging that D&B design and reconciliation practices were conducted inconsistently across operations, a Group wide initiative was launched to embed a standardized design and reconciliation platform in line with the company’s Operating Model principles. A technical system was selected to deliver the digitalization of critical D&B information and enable ‘analyze and improve’ routines for design compliance monitoring and downstream productivity optimization.

Jan 1, 2019

By Robert Cefalo

Drill and Blast Engineer Abstract In 2019, the Bingham Canyon Mine, owned by Rio Tinto Kennecott Utah Copper Company, mined through the active underground that dewaters the pit. The active underground required the limitation of vibrations to avoid catastrophic damage or damage that would require work to the shotcrete and additional roof support. The surface design of the current sector next to and through portions of the active underground. The drill and blast group was required to test site law vibration parameters to ensure that vibration limitations were lower than limits set by the underground management team. Seismographs were used to validate the vibration prediction model and check performance of blast in areas of the underground. The bench conditions and limited pounds-per-delay created large obstacles for the blasting team, making it difficult for them to accurately load the pattern with the number of decks in the blast. Methods were used to improve the loading instructions and ensure that each hole achieved pound requirements based off of the distance to the underground that it was designed to protect. The project evolved from start to finish, and the process to estimate distances and loading improved to make the blast a more repeatable process for the size of the project.

By Alan Bauer

During the past several years, the trend to large-diameter blastholes in both open pits and underground mines along with the continuing developments in slurried explosives and delay systems has kept things exciting for the drilling and blasting engineer. This has been particularly so in underground mining, where new mining systems having lower cost and higher productivity have emerged. Crater technology has produced new large-scale methods for resisting front penetration in tar sand mining and also new underground retreat mining methods and methods of raising.

Jan 1, 1978

By Sarah Guzzelli, Enrigue Munaretti, Anneliese Botelho, Jair Koppe

Drill and Blast (D & B) is one of the main operations in the mining production cycle, which aims to fragment rock according to a pre-defined plan for proper loading, haulage and processing specifications. In this sense, data from a Brazilian iron ore mine was analyzed, given emphasis on blasthole length, subdrilling and stemming. The D & B report, including mining data such as number of blastholes, length, and diameter and stemming aspects, was analyzed in order to be able to compare these results with the blast design. The study showed significant differences between the designed blasting pattern and that one obtained by the operation. As a consequence, problems such as inadequate fragmentation, incorrect size distribution and loss of energy, were identified. For example, when stemming has a different length than it should have, noise and flyrock can occur, including inadequate fragmentation and vibration in both situations. Therefore, a comparison between the usual D & B procedures and recommended D & B design based on literature reveals the most important deviations and their consequences. The study intends to identify solutions for simple problems, improving D & B operations and safety practices.

Jan 1, 2014

By Eddie L. Catbagan

The Escalante silver-bearing deposit, consisting of a relatively wide and continuous quartz vein, contains openings ranging from minute to a few feet wide on the footwall and hanging wall. These openings (water courses or vug holes) are I believed to have been created by the fluctuation of the water table.

Jan 1, 1983

By Laurence Neufville

Proper risk assessment and blast design are very desirable to the execution of a blast. Not only will this ensure that it achieves its desired outcome, but the probability of complaints and litigation will be reduced. Blasting engineers rely heavily on site-specific data for analysis and input to the blast design equations, and therefore data collection is critical to this process. The traditional approach to data collection is to carry out site-specific reconnaissance by visiting the site, but the time spent doing so can be reduced if a remote sensing approached is adopted.

Jan 1, 2009

By Krishna Nand

For assessing the safety of structures during underground explosions, ground particle velocity gives the best damage criteria, and 100 mm/see of ground particle velocity has been internationally accepted as the threshold value of safety (no damage). Results of extensive controlled underground explosion experiments conducted by the author to study the effects of ground vibrations on specially prepared concrete blocks, and also on low rise buildings and dams showed that no damage normally occurred when ground particle velocities were less than 100 mm/sec. Analysis of a large number of accelerograms from a dam site in India also indicated that no damage occurred to normal structures when integrated ground particle velocities were less than 100 mm/sec. Major damage in well built structures like a dam was noticed for ground particle velocity as high as about 350 mm/sec. These results are also generally substantiated from damage data obtained for various structures during other earthquakes, including Elcentro (1940), Taft (1952), Parkfield (1965), and San Fernando (1971). These studies, therefore, suggest that the damage criteria during underground explosions and earthquakes are similar; and 100 mm/see of ground particle velocity seems to be the general threshold value of safety (no damage) against ground vibrations.

Jan 1, 1988

By Shijie Qu, Paul N. Worsey

Pre-splitting has become widely adopted for the formation and protection of final surface rock excavation profiles in both large scale civil construction and highway rock cuts. Jointing has been shown to affect the success of pre-splitting and the smoothness of the resulting profile, however, only closed joints have been investigated. Frequently jointing that is closed at depth is open at and near the surface due to weathering, reduced stresses and ground water percolation. In many instances, problems are associated with surface rock layers whereas at depth these problems are either reduced or do not exist.

Jan 1, 1987