Search Documents

By Yong Pan, Purushotham Tukkaraja

In this paper, CFD was used to investigate the blasting toxic fume characteristics under different entrapping percentages and under changing muck pile properties like broken rock size and porosity. It showed that CFD was a very useful method to study blasting fume in an underground mine and it took much longer time to dilute toxic fume into a safe level with higher entrapping percentage. The dilution time increased with a decrease of broken rock size and porosity.

Feb 1, 2020

By Ery Wardhana, Stefanus Jagad, Relinda Sanistya, Hasucita Tausi, Rido Situmorang

The blasting process is one of the most high-risk activities in mining operations. Shotfirers and blasting crews face hazards from slope failure, toxic gas and fumes, or unstable ground condition every day of the blast. But on the other hand, to ensure all of the holes are detonated, shotfirers are required to reenter the location to check. With advances in technology, nowadays the use of drone in mining is not something that is rarely seen. It has been used for mapping and slope-monitoring. This paper will discuss the application of drone for blasting process in a mining pit in East Kalimantan, Indonesia. By using drones, it is not only safety factor which can be improved but also operational efficiency and technical analysis. The duration it takes for post blasting process can be reduced because the drone can directly enter the location after blast. The technical analysis for the blast can also become more comprehensive, as the before-after photos and video documentation can be taken with wider view. It helps with fly rock calculation and fragmentation analysis too.

Feb 6, 2023

By Randy Wheeler

In recent years the issue of seismograph calibration and accuracy has been a major focal point of the ISEE Blast Vibration and Seismograph Section. In fact, questions concerning the consistency and reliability of seismograph measurements essentially led to the development of this ISEE section. One of the early actions of the section involved the development of “Field Practice Guidelines” for the use of seismographs. These guidelines specifically state that “Placement and coupling of the vibration sensor are the two most important factors to ensure accurate ground vibration recordings.” This paper will address the results obtained from using different coupling methods to record vibration and airblast levels generated from production blasting in a limestone quarry. The data obtained clearly indicate that seismometer burial provides the best coupling for recording ground vibrations. Microphone height has also been an issue regarding the accuracy of recorded airblast levels. The data we obtained indicates that microphone height is not a significant factor.

Jan 1, 2004

By Gary Cavanough

The spontaneous exothermic reaction of ammonium nitrate explosives with sulphide-containing rocks, commonly referred to as reactive ground, is a site-specific condition that can lead to spontaneous detonations. Mine sites typically carry out regular assessment of ground for reactivity. In Australia, reactive ground testing is conducted according to the Australasian Explosives Industry Safety Group (AEISG) Code of Practice. This paper presents a new method to assess reactive ground. The new method can be completed on the mine site or in the laboratory. The new method allows samples to be tested in hours not weeks, as required when using the method prescribed in the AEISG Code of Practice. The new method also provides an explanation of why ground is reactive or not reactive, Whereas the AEISG Code of Practice provides a reactive, not reactive or marginal results with no understanding of reason for these results. Case studies on the use of weathering agents, pH, sulphide content and carbonate content will be reported. These case studies identify instances where the testing as per the AEISG Code of Practice provides false positive and false negative results. A false positive result will require the use of inhibited products when they are not actually required which increases costs and reduces productivity due to the need to used multiple explosive products. A false negative result increases the risk of an unplanned initiation of a blast hole.

Feb 6, 2023

By Lyle Avey

For the purpose of this paper, testwork and general pre-splitting practice will be discussed for the Chimney Creek Mine.

Jan 1, 1990

"Blasting is an inherently destructive process and inflicts damage to the immediateperiphery of an excavation, which is later manifested as ground control and dilutionproblems. Different explosives release their energy and interact with the rock in differentways."

Jan 1, 1993

By Willard Pierce

Very few people will consciously decide to do an unsafe act. With that said, how many of us unconsciously put ourselves in harms way, sometimes even on a daily basis? Complacency on the job may have very little to do with not caring or a poor attitude. It may be just as simple as failing to continue to recognize the hazards surrounding us throughout the day. At the very worst, it is both.

Jan 1, 2006

By Dale Nies, David P. Childs

The open pit gold and silver mining operations in the State of Nevada have historically used simple row by row, echelon, or chevron delay patterns. Common practice has been to use detonating cord trunklines and either detonating cord downlines or nonelectric common in-hole delays in conjunction with surface delays. Several operations use a series of downhole nonelectric delays with an entire row loaded with the same delay to develop similar patterns.

Jan 1, 1991

By Stephen Hamilton

This case history details the issues surrounding the rock drilling industry’s growing demand for straight holes, the importance of straight holes and the introduction of a new production drilling systems that can effectively and economically drill a true bore hole. Since the introduction of the hydraulic rock drill, the rock drilling industry has asked for a drilling system that would provide the fast penetration and low operating costs of Top Hammer drilling systems combined, with the directional control of Tube or DTH drilling techniques.

Jan 1, 1999

By Paul Worsey, Robert Sickler

Today, America's mining and construction industries are faced with operating under a condition of reduced profit margins. This makes the implementation of new technology far more sensitive to investment return than ever before. For this reason it is imperative that every effort be made to insure that new equipment and processes be designed to maximize their impact on improved quality, reduction in production cost and enhancement of safety. Using these principles as a foundation, a study was made to evaluate potential automation techniques for the blasting industry.

Jan 1, 1987

By Marlyn G. King, Robert L. Martin

Blasting activities in all four pits at Thunder Basin Coal's Black Thunder Mine are focused on cast blasting. With widths varying from 190 feet to 265 feet and bench heights varying from 90 feet to 175 feet, casting efficiencies vary with different geometry's. For example, the percent cast to final in the 200 foot pit is on the average higher than the 270 foot pit. The powder factors are somewhat higher in the narrower pits, thus increasing the cost of blasting. This leads to a very detailed look at the actual benefit of cast blasting and the associated cost of these benefits.

Jan 1, 1995

By John A. Huber

At an underground limestone mine in the Central United States; there were plans for the installation of a limestone processing plant. The special design and layout of the plant called for the installation of a tunnel from the underground mine to the surface above. The dimensions of the tunnel would be 10 feet high, 20 feet wide, and would be 500 feet long on a 17 degree incline. The tunnel would be used for the transportation of raw stone to the surface by a conveyor. A second conveyor would transport processed limestone into the mine for storage, that would be loaded out for shipment later.

Jan 1, 1995

By Mark S. Stagg, Rolfe E. Otterness, Stephen Rholl

The Bureau of Mines is engaged in research to develop and test high explosive fracturing and rubblization techniques that will enhance ore body permeability and thus increase recovery during in situ mining. The natural permeability of many ore bodies is too low to allow successful in-place leaching. These deposits could be profitably mined if flow rates of leach solutions could be increased. Blasting represents a potentially low-cost and effective permeability enhancement technique.

Jan 1, 1991

By R. K. Wharton

A European Directive requires that an explosive which is sold or transported within Europe must meet certain essential safety requirements from 1 January 2003. The assessment and certification of such an explosive is undertaken by an Explosives Notified Body and if the explosive meets the requirements a certificate is issued that allows the affixation of a CE mark. The presence of a CE mark ensures the product free access to European markets. The paper examines the requirements of the Directive, identifies those explosives that come within its scope, considers the role of an Explosives Notified Body, and explains the process of applying for certification.

Jan 1, 2002

By RR Vandebeek, A W. Bauer

The Canadian Explosives Research Laboratory regularly evaluates the properties of commercial explosives for authorization under the Canada Explosives Act. Propagation sensitivity is normally measured using small scale tests. Relating the results in actual mining practice is difficult. In the mining industry, the propagation sensitivity is a measure of the ability of one cartridge to propagate to an adjacent cartridge in a borehole. They may be separated by a gap of in-filling material. As well the propagation sensitivity will be affected by the explosive type, temperature, degree of coupling, cartridge diameter and other factors.

Jan 1, 1987

By Dale S. Preece, Ruilin Yang

"Air-decks are often employed for presplitting along the final highwall of a blast and are sometimes also included at the bottom or in the middle of explosive columns in the production portion of a blast. Shock wave physics is an important part of air-deck behavior since the bulk explosives in the column impart a shock into the air-deck where the air shock then passes through the air-deck at a rapidlyattenuating velocity. Through both high-fidelity modeling and shock physics theory it is shown that theresulting pressure in the air-deck is two orders of magnitude less than the detonation pressure of theexplosive."

Jan 1, 2017

By Michael S. Wieland

Toxic fume concentrations from industrial mining explosives depend somewhat upon the type of rock (or other strata) confinement. Though traditional detonation theory disregards this influence, the work principal from thermodynamics reveals it, when the violent interactions that transpire within the rock blast are taken into proper account. Resolution of the work principle technique requires total thermodynamic equilibrium under constraint, so the nonequilibrium dynamics is rendered in that way, using an old trick from theoretical mechanics that revises the representation of forces. The rock pressure reduces to a four-component sum: the rock compressive strength and natural atmospheric pressure, as reckoned quasi-statically, and the gravitational influence and reversed inertial resistance, as reckoned dynamically. Tabulated specie concentrations and graphical trends reveal the dependency upon rock pressure, rock temperature and the fuel-oil percentage in ammonium nitrate mixtures (ANFO), used to illustrate the model. Rigid-wall test chambers have notable ullage (residual space), where rapid expansion influences the reaction quenching, yielding a fume spectrum unlike that for rock confinement; reported rock tests are therefore used for comparisons. For the thermodynamic regime where quenching occurs, seven concentrations are resolved, including carbon monoxide (CO) and total nitrogen oxides (NOX). Their trends yield inferences regarding the way unwanted charge desensitization from transitory hole-to-hole wave impact in conjunction with reduced rock pressure can yield nasty toxic fumes, the dark rusty cloud phenomenon!

Jan 1, 2005

By Charles Clark, Mark Mukhija, Jaime Klein

Comminution – the reduction in size of solid materials – is the most energy intensive component of the mining process (Bauer, 2015). It is estimated that comminution consumes around three percent of all electricity generated in the world (Ceecthefuture.org, 2017). On an energy equivalent basis, downstream processing consumes six times more energy than drilling and blasting (Kanchibotla, Sarma et al., 2014).

Jan 1, 2018

By Denard Brandt, Isidro Martinez, Greg Baker, Laura Slattery, Teddy French

The Dos Pobres Mine is a copper oxide heap-leach mine located near Safford, Arizona. Mine production is 180,000 tons (163,293 tonnes) per day with a stripping ratio of 2:1. During the startup phase of the mine, the required fragmentation size was easy to achieve as the ore was highly weathered and fractured near the surface. As the mine depth increased, the proper fragmentation size became harder to achieve due to less weathering and different rock types. Because copper recovery increases as crusher product size decreases, achieving the appropriate product size at the crusher is the operating priority.

Jan 1, 2010

By Jorge Cárdenas, Gustavo Huerta, Regina Rocha Oriundo, Miguel Angel Humpire, Johan Salas Flores

Currently a critical activity for slopes stability and safety in mining is pre-split blasting to reduce damage from trim blast. Most common explosive used are based on packaged explosives, with 1 ½ in diameter cartridges initiated by detonating cord. Traditional loading process requires a significant amount of trained personnel, which in our application context could take up to 20 blasters. When pre-split blast is scheduled, it usually reduces the availability of the blasters on the total loading services at site which are also demanded to have production blasting ready at same 12-hour shift daylight time.

Feb 6, 2023