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This paper is concerned with the blasting of rock in mining. The most common purpose of blasting rock is to cast it or to disrupt its structure sufficiently for effective digging and subsequent removal.

Jan 1, 1991

By B Mohanty, Y C. Lizotte

Optimization of blast fragmentation in underground hardrock mining requires analysis of its effects on loading and haulage equipment, together with the downstream materials handling system, with the objective of minimizing total mine operating costs. A methodology is reported which has been developed to quantify the actual fragmentation and equipment performance in the field. This is data which has seldom been practicable to capture nor received serious attention in mines. Based upon the experience gained in underground studies, a prototype standard is proposed which aims to summarize the pertinent data, collection and analysis for fragmentation assessment. This relates to parameters of direct measure, such as mean size and distribution, as well as muckpile and work environment. The paper concludes by defining the impact of fragmentation on the loading and downstream handling system.

Jan 1, 1991

I was lucky to land a job in the powder business. I was looking for some way to support my wife and first child to be when I saw an ad in the Hercules magazine, “Explosives Engineer” for technical representatives. I answered the ad in hopes that a geologist might find something else to do besides sit oil wells or “doodlebug” for oil. Both of these occupations I had tried and while the money was good the life was a bit erratic. The Army also wasn’t made for a guy who asked too many questions although my two plus years in uniform were interesting and in a few cases fun.

Jan 1, 2004

By Douglas A. Anderson

The simplest method used to predict ground vibration from blasting is scaled distance -the distance from a blast divided by the square root of the Pounds per delay. Pounds per delay is defined as the number of pounds of explosive detonated within an 8 millisecond (ms) interval. Based upon this definition, regression plots of peak particle velocity vs. scaled distance have been used to determine likely values of peak particle velocity.

Jan 1, 1989

By R. Singh, M. Roy, D. Singh

Success of a blasting pattern in Blasting-off-the-solid (BOS) in Bord (Room) & Pillar method of coal mining is judged by the percentage of pull achieved vis-à-vis the yield of coal produced in a blasted round. Improper blast design and distribution of explosives in shot holes normally causes poor breakage i.e. a major portion of shot holes left unbroken resulting into reduced yield per blast. Over and above the disturbance to the roof is also due to excessive vibration caused by explosive energy not properly utilized in fragmentation.

Jan 1, 2003

By Sarma S. Kanchibotla

In overburden cast blasting the explosive energy is used to move a significant percentage of overburden from the high wall to the spoil pile thus reducing the amount of material to be handled by machinery. However, the obvious trade-off between the extra explosive energy in the cast blast versus reduced dragline effort is complicated by an increased risk of damage to the underlying coal. This damage may not be obvious but inevitably leads to reduced coal recovery and may negate much of the benefit sought from cast blasting.

Jan 1, 1999

By Detnet Solutions

1. “Daisy-Chain” concept The term “daisy-chain” stems from the fact that when the HotShot? detonators are connected there is a chain or electrical path for electrical current to flow from detonator A to detonator B, detonator B to detonator C etc until the path is terminated by an electrical means. The “daisy-chain” concept has long been used in electronic detonator systems, historically used in Expert Explosives’ ExEx 1000 5/6 wire system and currently in use in African Explosives Limited (AEL’s) Electrodet? electronic detonator system and has been adopted as the basis upon which the “auto-programmability” of the HotShot? electronic detonator system functions. HotShot? Detonators are connected to each other in a string, completing a “daisy chain”, and during the auto-detection mode of the control equipment, it is possible for the equipment to determine the order of hookup of the detonators as well as map the entire blast layout. The auxiliary components (Row Controllers & Branch Controllers) assist the control equipment in mapping the entire blast by indicating different points on the blast, i.e. The inflection point of a row of blast holes on a closed chevron timing pattern, the beginning of row of blast holes on open chevron timing pattern and extra blast holes or extra blast rows.

Jan 1, 2004

By Michael D. McGill, Jeff Freadrich

There are many factors which affect the productivity of a front end loader. One of the most obvious is the characteristics of the material being mined. Characteristics such as size distribution, swell factor or heave, and material hardness / abrasiveness will all effect the efficiency of the mucking cycle. The focus of this paper is to look specifically at the size distribution of blasted material, and quantify the effects on loader productivity.

Jan 1, 1994

By Frank Chiappetta, Karl Zipf, Robert Hopler, Brian Stump, Francois Heuze, Bob Martin, Vindell Hsu, William Walter, Craig Pearson

The Comprehensive Test Ban Treaty (CTBT) was accepted for signature at the United ,Nations in September of 1996. It ‘now awaits ratification by its signatories, ~including the United States. After the Treaty is in force, the main concern of the international community twill be to verify that no nuclear test is performed.

Jan 1, 1998

By H. Rossmanith

This contribution introduces the fundamental concepts of wave propagation and fracture mechanics which form the basis of electronic blasting, i.e. precise initiation timing using electronic detonators. The concept of Lagrange diagrams will be frequently used for the calculation of the delay time between blast-holes in a row and rows of blast-holes. The effect of burden and structural geology will be briefly touched. It is found that the advanced blasting technology based on the use of electronic detonators introduces a change of paradigm. It will be shown that knowledge in wave propagation and fracture mechanics is essential for the successful application of the new blasting technique in industry. In particular, the delay time, the wave speeds in the rock mass, the shape of the wave pulse and the acoustic impedance mismatch have become decisive parameters in advanced blasting. Utilizing the wave speed and wave shapes of detonations, large scale tests Utilizing the wave speed and wave shapes of detonations, large scale tests in various countries (Australia, Chile, etc.) have shown that optimal delay timing requires shorter delay times in conjunction with allowing for a wider drilling pattern and the use of a reduced amount of explosives, i.e. a lower powder factor. This seemingly contradictory arrangement is fully justified by using scientific principles in blasting, and converting blasting from an art to a scientific discipline.

Jan 1, 2003

By Wes Bender

Considering the current interest in Global Positioning System (GPS) usage, it might be timely to look at a more efficient means of utilizing these instruments. The GPS system currently utilizes 28 satellites (4 are spares) circling the earth in an inclined orbit. Normally at least six satellites are within your area of reception at any given time. The satellites broadcast an extremely accurate time signal and an almanac containing all the satellites’ orbital data. This information is updated regularly as the satellites circle the earth. Your GPS receiver, once it has picked up one satellite’s broadcast, can then determine which other satellites should be available for plotting.

Jan 1, 2002

By J M. Laboz Bernard

Among the numerous technical evolutions in the blasting environment we are going to describe below the concep

Jan 1, 1995

By David Ziegler

A formal blast plan is sometimes required for projects involving rock excavation. A written blast plan submitted with a bid proposal can also be an important sales tool. A blast plan will cover the basic elements of shot design: hole diameter, spacing, burden, loading, and so forth. Some suggestions are discussed here for additional items or topics to address, including: safety issues, ground control, traffic & site control, public relations, pre-blast inspections, seismic monitoring.

Jan 1, 2003

In the office, on the wall to the right of my desk is a large map of the world. Some people stick pins in maps like this to show where they’ve been. If I did that my map would be a mess and look like a pin cushion. I was so fortunate to have been able to see how people live and blast in other parts of this beautiful planet. We l l , maybe some parts weren’t so beautiful and maybe some parts that were beautiful were hell holes for those living t h e re . Every time I re t u rn to the good old US of A, I say a small prayer in thanks for having been born and raised in a land of freedom and plenty. So many places and people have not been so blessed.

Jan 1, 2004

By Thierry Bernard, Phillipe Cappello, Jean Marc Laboz

"The main reasons of the emergence of electronic detonators are linked to:-Local urban development close to mining operation sites-Environment regulations"

Jan 1, 1995

By Jerald E. Harris

"Often taken for granted, drill accuracy plays a major role in the relative success or failure of a blast.Expensive technological advances in equipment capabilities, drilling tools, communications, explosives, and timing can quickly be nullified by poor drilling."

Jan 1, 1999

By W. J. Birch, M. Kirke

Despite increasing competition from mechanical methods of tunnelling, the drill and blast method is often still the most viable method of excavating tunnels in strong and abrasive rock. To advance a tunnel using drill and blast, explosives are loaded into boreholes in the rock and detonated according to a prearranged sequence. On detonation of the explosive, the rock is fractured and displaced from its original position, leaving behind the desired void. Among the secondary effects of a tunnel blast are ground vibrations caused by elastic disturbances that propagate away from the blasted tunnel face. The possibility that such ground vibrations may cause permanent damage to property and substantial nuisance has generated significant opposition to the use of drill and blast, particularly in urban areas. It is therefore essential that the blasting engineer is able to predict Peak Particle Velocity (PPV) vibration levels at locations in the vicinity of the blast site. Such predictive capability enables the engineer to design blasts so as to ensure that ground vibrations can be kept within acceptable levels. The objective of this project was to analyse data obtained from the ground vibration monitoring program undertaken during the drill and blast excavation of a hard rock tunnel in Central England. Seismograph recordings of tunnel blasts contain a vast amount of information that cannot possibly be expressed using a single PPV value. The main focus of the study was to investigate whether predictive capability could be improved by using scaled distance models derived for selected PPV components relating to specific detonator timings in a given tunnel round. This study has established a method of analysis that can unlock this information for predictive purposes. By permitting the extraction of sub-event Peak Particle Velocity (PPV) values and allowing Scaled Distance (SD) models to be derived for individual period numbers or groups of period numbers, the method has the potential to vastly improve PPV prediction from tunnel blasting. The method established could also help diagnose blasting problems and help target blast design modifications, resulting in improved efficiency and excavation rates.

Jan 1, 2005

By A. Feldman

Measuring dynamic effects on existing structures such as dams and bridges during earthquakes or blasting is frequently done using strong motion detectors. However, a more comprehensive dynamic structural evaluation requires direct measurement of deflection, strain, and pressure changes during dynamic events. Many existing structures have vibrating wire gages already installed that can be used with modifications to the data acquisition systems to provide direct measurement of dynamic displacement, strain, and pressure. The project described in this paper provided the opportunity to demonstrate the feasibility of using vibrating wire technology to measure dynamic effects on existing structures.

Jan 1, 2006

By Kate Satish

M/s Konkan Railways Corporation are constructing 760 kms long rail road in the Western Coastal Region of India. The rail road encounters 75 tunnels through the Western Ghats of India with a total length of 78.35 kms, the longest tunnel being 6.5 kms long. The tunnels are of horse shoes shape having a cross section of about 37 Sq.meters

Jan 1, 1996

By Jorge Cárdenas Miranda, Hector Espinoza

Currently in open pit mining in Peru with double bench, it is a challenge to optimize fragmentation in the drill rows near to the slopes to ensure the performance in the loading and haulage operation along with the process in the plant. That is why the present paper addresses a previously unanalyzed variable on the effect of the discontinuity plane on the fragmentation results. From the numerical mathematical models applied through algorithms in advanced computational tools such as Elfen, it was quantified the improvement in fragmentation results as P80 through a correct pre-split plane both in its extension as well as in its width. The first results show an improvement of 30% in the P80 and ensuring the quality of the walls without damage to the matrix of the final wall. The basis developed in this paper is based on the concept of wave reflection in the free face zones where greater efforts are presented for fragmentation, a similar theory is presented in the variation of initiation sequences that seek a greater area of reflective planes in the form of "V". Cases were evaluated with a percentage of compliance of the pre-split planes from 0 to 100% evaluating the impact on the results and correlated with field information explaining the behavior and validating the benefit. From the quantification of the benefits, this work opens the possibility of focusing resources on optimizing the pre-split process to achieve an improvement in the fragmentation results, giving a greater tool in the decision to optimize the blasting process.

Feb 6, 2023