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By K Lombardo

Numerous small- and intermediate-size cratering experiments have been conducted in Piceance Creek Basin oil shale at the Colony and Anvil Points oil shale mines near Rifle, Colorado. The purpose of these experiments was to evaluate scaling as a tool to infer the behavior of large-scale tests from small-scale experiments, to calibrate the hydrodynamic computer codes used to model explosive fragmentation of oil shale, and to investigate the influence of bedding plane orientation, natural joints, fractures, and the grade of oil shale on rock fragmentation.

Jan 1, 1983

By C F. Argo

In the past several years the "Kelly Bar", an innovative device, which incorporates borehole d-rifling and explosives loading into a single detail, has come under scrutiny and criticism. The practical aspects of the Kelly Bar procedure is not questioned, and the system has been highly successful in expediting the loading of explosives in difficult and unstable formations. There have been a number of accidents indirectly associated with Kelly Bar loading and the point in question has become one of safety rather than mechanical feasibility.

Jan 1, 1975

By Karl Ingmarsson

A model for drilling productivity and total drilling cost is presented. It specifically addresses down-thehole drilling, but also covers other drilling methods. The important factors are: 1, productivity in tons drilled; and 2, total cost per drill ton. For non-blasthole applications these factors are measured in drill feet and cost per foot. The model focuses on the entire system and allows the operator to optimize the system based on individual drilling conditions.

Jan 1, 1998

By M Scoble, J Szymans

During the past year, the Canadian Centre for Automation and Robotics in Mining (CCARM), McGill University, Montreal, has been involved with INCO Ltd.'s Manitoba Division in investigating the extent and mechanisms of blasthole deviation. Drilling accuracy can well be regarded as perhaps the single greatest "controllable" factor influencing dilution in INCO's open sloping operations. As INCO and other underground mines seek to minimize dilution, while attempting to maximize productivity, issues of drilling accuracy become increasingly significant. It is important therefore, that means exist by which true blasthole trajectories can be determined, so that if needed, modifications to hole loading instructions or redrilling of holes can be ordered, thus avoiding poor blast results.

Jan 1, 1991

By S. S. Bud Jenkins

I went to an underground limestone mine recently to demonstrate the use of borehole liners. The liners were for horizontal holes in a normal “V” cut tunnel round. I hadn’t been in this mine for about 40 years. What a change. Way back they used cap and fuse and lit each fuse individually with a blowtorch. The face was about 40 feet wide and 14 to 16 feet high. They used ladders to get to the upper holes. The rounds were mostly slab rounds. I never saw this happen but had heard several times that the first holes were going off before the last holes were lit. I guess if this was true the use of slab rounds was a plus for safety. As far as I know they never had an accident but it was a scary procedure. There were a lot of scary procedures in the past and thankfully things have changed.

Jan 1, 2010

By Zoltan Susanszky

The total available energy in an explosive charge is seldom fully utilized in industrial operations. For this reason more explosive is normally used to perform a job than we would calculate. In an explosive detonation some energy is generated as waste energy which can not be efficiently used. This results in added expense and possible environmental damage. This waste energy can create problems in metal forming with explosives and during commercial underwater blasting operations.

Jan 1, 1976

By Ruilin Yan, Kameron Ray

This paper reports a simple approach to model the waveform change due to travel distances based on the field measurement. A linear interpolation is used to estimate the waveform at a distance from two vibration waveforms recorded at two different distances. The resulted waveforms are compared with actual recorded waveforms at the point in both time and frequency domains. It shows that the proposed method to estimate the waveform change yield reliable results. The advantages of the proposed method are that it does not require assumptions that a transfer function does and that it is based on purely the measured waveforms that are encoded with in-situ rock properties. The method could be more reliable for far field seismic waveforms and could be an approximation for near field waveform estimation.

Jan 1, 2014

By Dieter Froelich, Giles Turcotte

In the near future, Bong Mining Company (BMC) will start mining a new deposit known as Zaweah II which is a narrow iron orebody requiring multiple row blasts with the bench floor as a free face. This called for the development of a new blasting technique. The article delineates the problem and its restrictions related to blasting. It also describes the approach which was taken for developing this new blasting technique which is essentially an application of the cratering theory with near spherical charges. Basic crater tests were conducted using various combinations of hole sizes, explosive strengths and delay patterns. From the results obtained, several alternatives were considered for production blasts and the most promising ones were evaluated.

Jan 1, 1980

By Dennis Alan Clark

An increase in construction and quarry operations has necessitated blasting activities in areas once considered rural and in the close proximity of transmission pipelines. A method to determine the maximum allowable bending stress by the formulas outlined by the Battelle Memorial Institute report of October, 1962, and the assumed stress comparison with actual measured data is presented. A direct relationship between pipe stress and ground particle velocity is shown, and a method to predict stress by relating stress to charge weight and distance from the shot point is discussed.

Jan 1, 1976

By Greg Mclellan, Mark Johnson, John Pepper

In this paper, the measured vibrations are plotted in terms of the individual PPV components versus Scaled Distance (SD) on logarithmic scales. The maximum PPV is pIotted on a separate graph and equations are presented to predict the maximum PPV based on sealed distance and prediction level usmg power fits. The prediction levels include a 99.9% curve, which encompasses the data points and provides an envelope formula for determining the maximum PPV at South Florida sites. The dominant frequency distribution is established for the PPV components.

Jan 1, 2001

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 Robert S. Mayo

Tunneling, for transportation, began in France with the Milpass Tunnel on the Lanquedoc Canal in 1680. Of course, the ancient miners had been driving tunnels in search of minerals since the dawn of history but this Milpas Tunnel was the first tunnel exclusively for transportation. In England in 1760, the Duke of Bridgewater opened a canal from his coal mines to Manchester, 10 1/2 miles away. At the mine, he drove a tunnel into the mountain so that the miners could shovel the coal directly into canal boats. James Brindley, an untutored genius, was his engineer and this whole transportation system was an instant success and very profitable through the years. Within a dozen years the Duke, again with James Brindley, opened up the Grand Trunk Canal, 139 miles in length with five tunnels. There was one major tunnel on this system, the First Harecastle Tunnel, 1 1/2 miles in length. But this tunnel was too small. It was only large enough for one 7-ft wide boat which had to be "legged" through by boatmen laying on their backs. By 1824 a second tunnel was driven parallel to the first one, but it had a towpath through it for horse haulage. This was the beginning of the " Industrial Age" and tunnels became a very important part of that era.

Jan 1, 1979

By Benedict C. Di Duca

In the underground construction industry. when bidding work, not only is the contractor faced with determining if rock: is in existence within the parameters of his work. he must also estimate the quantity and the most efficient method of removal.

Jan 1, 1990

By Roy McKinstry

In March of 2001, Barrick Goldstrike became the first surface gold operation in North America to evaluate the advantages of electronic detonators. A detailed study was conducted to quantify the benefits of the use of electronic detonators to the downstream excavation, crushing and ore processing operations. The following methods were used to quantify blast performance: High speed film and video monitoring Firing time and rock response analysis of the high-speed films Digital fragmentation analysis of the post blast muckpile Vibration waveform analysis (including Fast Fourier Transforms and seed waveform modeling) Excavator performance quantification Crusher, SAG mill and ball mill performance evaluation Ore recovery analysis Cost/benefit analysis

Jan 1, 2002

By Braden Lusk

A typical rural house surrounded by a surface coal mine was instrumented in 2008. Information regarding ground vibration, airblast, and sounds inside the house was collected. Previous publications have included conclusions about this data with regard to blasting source (far-field or near-field) and results as to how the residents experience the blast were made. Several events were also recorded that were not related to blasting due to the nature of the trigger system. The trigger of the monitoring system was attached to one of the mid walls of the house, thus other normal daily events produced vibration levels significant enough to trigger the monitoring system.

Jan 1, 2011

By A. Andrades, E. Arias, Y. Pizarro, J. Alarcón

Division Ministro Hales - Codelco (DMH) is located at 2600 meters above sea level, 10 km north of the city of Calama, Antofagasta region, Chile. In operation since 2010, it corresponds to a porphyry copper deposit that is exploited by the open pit mining method. The ore is mainly composed of sulfides, which is concentrated by comminution processes such as crushing, SAG milling and ball milling to liberate the mineral particles, and then separated from the waste (concentrate) in flotation stages, including a concentrate regrinding stage. Reports from the DMH processing plant area have identified a decrease in fine copper recovery, with the first hypothesis being the high percentage of ultrafine particles (% <45µm) in the flotation feed. Due to the above, DMH & Orica decided to carry out activities to identify the controllable variables that can impact the generation of low size particles in ore and adjust them to reduce the percentage of fine material generation, with special focus on the Drilling and Blasting processes. Based on the data provided by DMH, we evaluated what could be integrated to make an analysis. The different attributes associated with the ore and their effect on copper recovery were evaluated. In parallel, at the mine, a fragmentation measurement campaign was carried out at the loading faces and granulometric analysis of the drill cuttings. Once the correlations between the attributes and copper recovery were identified, hypotheses were established and reviewed with the Drilling & Blasting, Geotechnical, Geology and Process Plant areas. With the validations of the hypotheses and the results of the in-mine (cutting) measurements, we proceeded to review the criteria for the classification of Blastable Geotechnical Units and their associated D&B designs. Using software and the Crush Zone Model (CZM) tool, which considers rock and rock mass parameters, scenarios for various D&B design proposals were simulated with the objective of reducing the generation of ultrafine particles from the blasting process. Next steps include trial blasting with the D&B design recommendations, which will require follow-up to the flotation process to identify the impact on the reduction of ultrafine material from blasting.

Jan 1, 2024

By Deepankar Das, Gulshan Kumar Sadhwani, Jyoti Prakash Sahoo

Sindesar Khurd Mine (SKM), the largest underground mine in the Hindustan Zinc Limited portfolio, is located approximately 60 kilometers (37 miles) north of Udaipur. In the 2018 financial year SKM achieved an annual ore production of 4.5 Mt (4.42 million LT) and mined metal production of 247 kt (243,099 LT).

Jan 1, 2019

By Tony Francelj, D. Scott Scovira, Remi Proulx

The Meikle Mine is a high-grade, underground gold mine that utilizes a primary and secondary stoping method with delayed backfill. The newly developed Rodeo Mine will start production using similar mining methods in late 2001. The combined production for the mines will be 4100 stpd of ore in 2002. Dilution of the secondary stopes resulting from blast induced overbreak of the backfill placed in the primary stopes was an issue identified as being a major contributor to the total mining cost at the Meikle Mine. To address the overbreak issue, a low-density, polystyrene enhanced bulk emulsion was developed and introduced to the mine. The density and energy of the emulsion was varied until an optimal level was reached. The use of a low-density bulk emulsion has greatly reduced the overbreak of the primary stope backfill when blasting the secondary stopes. Benefits to the mines include reduced secondary stope dilution, lowered total mining cost, and increased revenues.1

Jan 1, 2002

By Robert L. Brooks

Blasting liability problems are frequently compounded by a company's inability to effectively communicate with concerned property owners and the lack of adequate complaint documentation. Often, by the time the insurance carrier becomes involved in a blasting claim, the situation has deteriorated to the point that a solution agreeable to both parties is virtually impossible to reach. The insurance carrier, wishing to minimize their lose potential may decide to pay on a somewhat questionable blasting claim rather than be drawn into lengthy civil proceedings that would ultimately end up in front of a jury with little chance for a successful outcome.

Jan 1, 1992

By Robert B. Hopler

This paper reviews, from the historical standpoint, the development of the commonly-used terms such as "No. 6 and No. 8" with regard to detonator strengths. The origin of the strength terminology is reviewed, and the many methods developed to compare the strength of one detonator to another are described, with the good and bad points of each method outlined. The "miniature cartridge test," very highly regarded by both the U.S. Bureau of Mines and Institute of Makers of Explosives in the 1930's and early 1940's, is described in detail, as is a test developed and used by IRECO.

Jan 1, 1992