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By Peter Bellairs, Anthony Bubb

The Porgera Gold Mine is located at an altitude of 3000m in the central highlands of Papua New Guinea some 600 km Northwest of Port Moresby the capital city. Access to the mine is via a five hour trip on an unsealed road from Mount Hagen the nearest regional centre or 40 minutes via air. The mine operates on a fly in - fly out basis and currently produces ore from both opencut and underground operations with the former providing the bulk of the mill feed. Opencut mining utilises conventional truck / shovel, drill and blast methods on both 10 metre and 14 metre bench heights with the larger benches being restricted to the stripping areas. This paper presents the strategy used and the results of a blast optimisation process in the opencut that was a joint effort between the mine personnel and the explosives manufacturer/supplier.

Jan 1, 1997

This paper examines the hypothesis that the fragment size distribution of blasted rock contains information about the changes in fragment sizes with distance from the borehole, and that this information can be interpreted and used to predict the effect of powder factor on fragmentation. A set of simple relationships between the fragment size distribution curve and the dependence of fragmentation on powder factor is proposed. The equations derived are compared with published data on fragmentation in small scale blasting. Two data sets were analyzed, and the results confirm the hypothesis.

Jan 1, 1997

By John Watson

The earliest known records related to mining document in dramatic terms the fact that mining methods have undergone significant change over the centuries. Wooden wedges, hammers and chisels, “fne setting”, to name a few, were the frst tools used to extract ore .or quarry rock for civilization. These inefficient tools and unsafe practices have been replaced today with some of the highest technology known to man. At the heart of most mining operations is the blasting program which utilizes one of the most efficient tools ever invented.. . explosives. Ever since they were invented, miners have been searching for more efficient products and methods with which to harness this “tool” and make it safer, reliable, and more eficient to use.

Jan 1, 1997

By Trevor Howie, Mal Edwards

"Thiess Contractors Pty Ltd. designed and operate the Mt Owen Mine in the Hunter Valley of NewSouth Wales, Australia on behalf of the owners of the mine, BHP Coal Pty Ltd. The mine is a multiseam open cut coal operation. Mining by Thiess commenced in September 1996 following thecompletion of the coal preparation plant. The location of the mine is shown below on Figure Al."

Jan 1, 1997

By Gregg R. Gitschlag

There are more than 4,000 oil and gas structures present in the U. S. Gulf of Mexico. Approximately 100 structure removals occur each year and 66% of these are removed with explosives. From 1993-1995 an intensive study was conducted on the fish kill resulting from the explosive removal of 6 platforms off the Louisiana coast in water depths from 14-28 m (45-92 ft). After explosives were detonated, all floating fish and a sample of the dead fish which sank to the sea floor were collected.

Jan 1, 1997

By David Reddick

The mining industry is in the midst of dramatic change. Mining activities are moving from industrialized first world countries (Canada, Australia, and the United States) to the third world. This shift is occurring due to depleted reserves, tough environmental standards, and expensive labor in traditional mining countries. During a recent trip to South Africa, I was asked, owing to my educational background in economics and an international involvement in drilling and blasting, what changes could be anticipated in third world blasting practices as labor costs increase. It is from that beginning that this presentation has evolved.

Jan 1, 1997

By Brad H. A Brown, J Paul Tidman

To design a blast, one must give consideration to safety, economics, geometry, geology, production needs, and a variety of other requirements. To compare designs requires the time to develop alternatives, analyze, and then improve on them. A number of tools are available to assist with the first set of requirements, however they are poorly integrated. SHOTPlus is a program to improve the efficiency of blasting operations, by combining measurement and blast design tools, and offers the user the time and means to modify designs and explore alternatives.

Jan 1, 1997

By Gordon M. Matheson, David K. Miller

Possible impacts to the water quality and production capacity of ground water supply wells by blasting is a common cause of complaints for blasting contractors, mining companies, and local regulatory authorities. The major complaints of changes in well water quality include; turbidity, discolored water (red, brown, black, yellow and milky water), and nitrate and/or coliform contamination. The major complaints for changes in well water production capacity include: loss of quantity production, air in water and/or water lines, damage to pump, and damage to well screen or borehole.

Jan 1, 1997

By Ola Lindahl, Mark Irving, John Hutchings

"Blasting is a process starting with a geometric description of the block of rock and ending with a pileof fragmented material. A key step in improving the productivity and quality control over the processis the integration of blast planning software, explosive delivery control systems, and blast recordingwithin one seamless customer solution."

Jan 1, 1997

By Katherine L. Heineken, Timothy J. Tope, Kim David Murphy

One method for small arms disposal is the use of a deactivation furnace or explosive waste incinerator. There are numerous hurdles a facility typically encounters to get the furnace or incinerator fully operational and permitted. For example, one Department of Defense installation was in the permitting process 7 years, which included numerous facility upgrades and modifications. This paper will discuss the technical approach for proactively addressing permitting issues and requirements and will identify potential pitfalls to avoid as well as ways to reduce costs. For example, when determining the waste profile, the facility should forecast its treatment needs (taking into account the net explosive weight limits of the furnace/incinerator) and then classify the wastes into "chemical families" based on the type and composition of the wastes. One waste from each family should then be selected for potential inclusion in the trial burn. Modeling the waste disposal can help to narrow down the number of wastes requiring characterization during a trial burn, as well as the number of analyses.

Jan 1, 1997

By John C. Didlinger

How do you measure the highwall? Why do you even need to know the highwall measurement? Why is it important? The importance of this measurement is to help keep a level floor and to help control vibration. Nevertheless, since most of us are not mountain climbers, there must be a safe and easy way to make an accurate highwall measurement. So with these factors in mind, how do you make your measurement?

Jan 1, 1997

By Jianjun Tang, Wenjuan Bai

This paper presents a new method of formulation design for multi-component composite explosives. Based on the thermochemistry of the detonation process, the mathematic model of formulation design is established by optimization mathematics. Using the heat of detonation as target functions and taking the constraint conditions such as oxygen balance and costs etc into consideration, this model can provide an optimal solution quickly by means of personal computer. Using this method, the calculation and the simulation tests for a series of constituent sets and various constraint conditions can be conducted easily. In this way, the optimal formulation for the explosive can be determined, on the basis of the maximum heat of detonation and the lower cost.

Jan 1, 1997

By Cam Grundstrom

The Ok Tedi Mine is a large open pit copper and gold mine located in a remote section of the Western Province, Papua New Guinea, with an annual rainfall of over 10 metres. Ok Tedi mines an average of 205,000 tonnes per day. A strong working co-operation between the mine operator (Ok Tedi Mining Limited) and the explosives contractor (ICI Explosives Asia / Pacific) has led to progressive development of bulk emulsion formulations to meet site-specific needs, continued improvement to blasting applications, and competency based training programs for the national blast crew.

Jan 1, 1997

By M S. Stern, R Aguila

To control direct blasting costs many open pit mines dewater and line wet blastholes before loading them with ANFO or Heavy ANFO blends of explosives. The plastic lay-flat tubing used for these liners can be punctured during loading and allow water to partly dissolve and desensitise the explosive column which reduces blasting performance.

Jan 1, 1997

By Laura Bastemante, Bruce Vandenberg, Fred Huettig

Recent advances in solid-state, field portable, fast framing video camera systems and PC based frame capture hardware now allow blast imaging up to loo0 frames per second. Up to 8 seconds of data can be stored directly into the unit, downloaded to a PC or archived to a standard VCR without data compression. Since no film processing is involved, motion analysis can be performed instantly and on-site within a few minutes. This paper will describe the design features and applications of the KineView 1256P system and compare these with the analogous aspects of film based cameras.

Jan 1, 1997

By Thomas M. Keevin, Gregory L. Hempen

Accurate assessment of blasting near an object (organism or structure) requires recording of the damage parameter for low-valued scaled distances. Seismograph recordings of particle velocity are a well established, common procedure for land-based blasting. Similarly, pressure recording of the absolute waveform needs to be a more common procedure for sensitive, underwater resources.

Jan 1, 1997

By He Guangyi

During rock blasting in extending deep cutting from Jiu Li Mountain to Dong Zhuang Village in Jiao Zhi Railway line, we have drilled deep hole with large scale diving drilling machine and successfully carried on controlled blasting. This has provided new experiences for rock blasting in extending existing cutting. The aim of this article is to provide an introduction to bench height, blast holes arrangement, powder charge calculation, and detonating technique during blasting.

Jan 1, 1997

By A Rorke, B Cubitt, R Beeslaar

The recent drop in the value of the South African Rand has resulted in an increased export value for South African coal and has lead to new coal reserves becoming available for mining. Very often these reserves are in close proximity to existing structures and utilities thus calling for stringent blast control measures to keep the risk of vibration, air blast and fly rock damage to a minimum.

Jan 1, 1997

By J Paul Tidman, Stephen H. Chung

One of the requirements in open pit gold mines is to minimise the mixing of ore and waste. Dilution can be reduced by choke blasting and control of the initiating sequencing. The authors have used the DMC computer model (developed at SANDIA) to examine the effects of timing and charge distribution on ore dilution. The model has been calibrated by measurements of vertical uplift derived from high speed videos made at the Dome Super Pit in Timmins.

Jan 1, 1997

By Chris Uys, Johan Labuschagne

Sishen Iron Ore Mine, located in the Northern Cape, is an open cast mine excavating approximately 100 million tons rock to produce 25 million tons of high grade haematite ore per annum. The size of the pit is approximately 12 km ‘1.5 km ‘150 metres. The final depth is planned to be around 350 metres. It is hard rock mining operation employing the conventional truck and shovel method. Mining benches are twelve and a half metres in height and are divided into blasting blocks, each consisting of approximately 300 000 tons of material.

Jan 1, 1997