Search Documents

By Sami Kara, Marsel Nabium

As a mining project is developed from conceptual to production phases, there exists a variety of uncertainties and difficulties that affect the operation’s designs and economic values. A notable design parameter to be taken into account is the factor of dilution. Dilution is the waste material not separated from the ore in the stages of mining and is sent to the processing plant. It is defined at the ratio of tonnage waste mined and sent for processing over the combined ore and waste tonnage milled. Dilution reduction is one of the areas that offer metal mines an opportunity to increase revenue and reduce costs, resulting in enhanced profits. Effective dilution control programs require interaction on a multidisciplinary level. This paper outlines recent initiatives undertaken at Polysmetal Silver Magadam Mine to reduce dilution and increase revenue. This paper provides an overview of the solution applied in underground Silver mine in Russia. The paper reviews the dilution problem throughout the entire mining process, and provides a rational approach to underground mine Blast design in order to minimize dilution. The mining companies put a lot of effort into extracting lower grade while minimizing cost. The dilution control assists with achieving this goal. In Polymetal Silver Magadam Mine we succeeded to control more than 20 blasts by keeping almost the same grade measured in the face. The results indicated that using the adequate blasting timing design can help to separate the ore from the adjacent waste in drift blasting with different ore body configuration.

By Ann Barron

For millions of people, cold weather is a fact of line – and one that can make a major challenge out of just getting to work. But for those working in the blasting industry, a number of obstacles are created when old man winter blows in. In addition to the obvious concerns regarding personal protection, Mother Nature can throw some very nasty weather at the blasting crew trying to travel with explosives products from the magazine site to the job site. As such, divers need to be familiar with cold, ice, and snow driving conditions both on and off the blast site. It’s critical to know what to expect before you leave. Keep informed of the latest weather and road conditions as they change often; it will help you make the right choice in clothing and driving habits. Remember bridges and overpasses will freeze first even in temperatures above or near the freezing mark due to the effects of wind chill. Plan to take extra time to and from the job site.

Jan 1, 2004

By Michael J. Sapko, Eric S. Weiss

The U.S. Bureau of Mines has been conducting research on the secondary explosion hazards associated with the mining of oil shale under gassy mine conditions. Explosive incendivity tests have been conducted in a 28 m~3 (1000 ft~3) gallery to evaluate the relative incendivity of experimental emulsion-ANFO blends. The incendivity was measured by determining the minimum inert stemming requirements for preventing the ignition of a methane-air atmosphere by the discharge of hot detonation products from a 5.7 cm (2.25 in) diameter borehole.

Jan 1, 1990

By Richard N. Snyder

In this system for connecting blasting caps to the initiation source, the need for a redundant design structure provides more reliable method of explosive initiation. This is accomplished by using a complete system starting at the blasting control, through the initiation line structure through the initiation line and connecting blocks to the blasting cap. The connecting structure between the initiation device and the blasting caps may be connecting blocks or other means.

Jan 1, 1995

By Mark Abernathy

When most people think of a motor vehicle accident, the direct costs resulting from that accident, such as vehicle repair or towing charges, are generally easy to quantify. However, the indirect costs associated with an accident are often overlooked. These indirect costs can take a tremendous toll on a company in more ways than you might think.

Jan 1, 2006

By Kush Patel, Gary Cavanough

Mining operations consume over 2.5 Billion Australian dollars’ worth of bulk explosives annually (Richardson, 2018). Despite the large volume of product used, current practices only conduct a cup density test of the product being used. Explosive products are made up of a number of components, each with an effect on the performance of the explosive. This paper presents methods currently available for the evaluation of bulk explosives and discusses the results of the evaluation of bulk explosives using each of the methods. Through the preliminary experimental analysis, wet chemistry and the Bulk Explosive Analyser were found as methods most suitable for the evaluation of bulk explosives. This paper also presents data obtained from the experimental comparison of the wet chemistry method and the Bulk Explosive Analyser. Through a total of 60 tests carried out on 10 different bulk explosive products the average error of each method was determined, the BEA presented an average error of 0.11%, whereas, the wet chemistry method presented an average error of 1.90%. This is a significant difference when considering the importance of formulation of explosives. Further investigation into the capabilities of the BEA are also presented in this paper.

By Kenneth Faroni, Catherine Aimone-Martin, Thomas Gelormino

A blasting improvement program began in 1985 at two traprock quarries in Connecticut to reduce the levels of ground motions and airblast measured at residential structures surrounding the operations. The quarries are situated within town limits, adjacent to a number of historical and other structures. Although blasting vibration amplitudes were found to be far below those that could produce cosmetic defects in structures, they were perceived to be the cause of structural defects observed by homeowners. Based on a comprehensive * review of blasting practices in place during1985, an extensive vibration monitoring program was implemented. The initial study included the instrumentation of selected residential structures to record and analyze strains imposed within structures from quarry blasting, environmental changes, and from daily household activities. A comparison of the results was made with the results reported by the U.S. Bureau of Mines in 1980. The highest strain imposed in drywall from blasting (13 J_I strain) was 12% and 1% of the highest strain levels recorded for normal household activities and temperature changes, respectively. The present philosophy in production blasting is to attempt to keep vibration amplitudes as low as practical by implementing state-of-art blasting control techniques. Currently, blasting seismographs are placed in a circular manner around each quarry, providing production blast vibration records for 360 degrees of coverage at distances of 2500 to 4000 ft. from blasting operations. Seismograph and production blast records are analyzed each year and become part of a Blasting Improvement Plan submitted to the local zoning commission as part of the annual operating permit process. This paper summarizes the results of previous vibration monitoring programs and outlines the modifications made to blasting practices to minimize the levels of ground motions and airblasts. The public relations efforts and standard corporate procedures used by company personnel to address all blast related complaints and alleged damage claims since 1985 are also discussed.

Jan 1, 2000

By Kwang-Tae Kim, Yong-Kun Choi, Jeong-Soo Chong, Yun-Jae Lee

An annex building at the former Agency for National Security Planning(NSP) complex located in downtown Seoul was demolished by progressive collapse method. This work was done as a part of efforts to restore the landscape of Namsan Mountain which lies in the Center of Seoul. The five-story reinforced concrete structure was razed in 5.5 seconds by the 29kg of high powered explosives which were placed in some 320 holes in the building with floor area of 2,577 m². The asbetos and all the other finishing materials in the building were removed before the demolition and the specially coated wrap minimized the spread of blasting dust. Seismic and air overpressure waves were monitored at 8 points, which were below safety limits and the continuous communication with neighborhood prevented any complaint.

Jan 1, 1998

The breakage mechnism of a spherical charge greatly differs from that of the cylindrical charge used in underground mining. The advantages of the spherical charge could not be utilized until INCO Metals Company, Ontario Division, introduced large diameter holes to their operation.

Jan 1, 1978

By Mo Jadbabaei, Scott Harrison

There is very limited information available regarding the air pressures, flow rate, and velocity profiles in blast hole air drilling applications. Currently, many people are using incompressible flow correlation to calculate the bailing velocity. In this article, air pressure, flow rate, and velocity profiles are calculated using compressible flow theory. The airflow at the bottom of the hole is simulated using the jet flow theory. The concept of choking condition is introduced, and it is concluded that the velocity at the nozzle exit cross section cannot exceed sonic velocity. The minimum pressure required for achieving choked condition at the nozzle cross section is calculated. Choked and overchoked flow conditions at the nozzles are examined, and the maximum achievable cleaning power is correlated to the nozzle size and pressure.

Jan 1, 1999

By Jim Breedlove, Stephen P. Case

When a major ground subsidence occurred in the AKZO Salt mine at Retsof New York, the company was forced to pick up their production from a lower mine level. Before full production on the lower level was possible, an escapeway and ventilation shaft would have to be constructed. Construction of a shaft under emergency conditions required some special techniques. Dynatec Mine Construction, Inc. of Lakewood Colorado was awarded a contract for the project.

Jan 1, 1995

By Rodney D. Lamond

The need for blast vibration monitoring can be attributed to a combination of three factors: Structural damage, Blast design and Human annoyance. Traditionally, vibration damage criteria are prescribed in terms of peak particle velocity (PPV), as measured or predicted in the ground surrounding a blast. The PPV in the vicinity of a blasthole is strongly influenced by the quantity of the explosive per delay. In general, the existing prediction models give reliable results but fall short of addressing the change in PPV when the charge is decoupled and/or distributed.

Jan 1, 1995

By George P. Jr Schivley

Looking at the process of drilling rock from the standpoint of the power required, yields an equation that relates Force-on-the-Bit; Torque, to rotate the bit; and bit Angular Speed to the Penetration Rate of the bit; the Area of the hole being drilled and the Specific Fracture Energy of the rock. Specific Fracture Energy and the Compressive Strength of the rock are related.

Jan 1, 1994

By Andrew F. McKown, Robert A. McClure

This paper will describe a trench blasting case history in close proximity to several adjacent structures, including a bridge abutment, railroad tracks, and utility pipes. Some design considerations involved in close-in blasting will be discussed, including allowable peak particle velocities and prevention of rock block movement. The importance of several trench blast round design factors is pointed out, including choice of explo sive to prevent propagation, maintaining a sufficiently high powder factor, and mucking out for maximum relief after every round. Vibration monitoring and good record keeping are shown to be important in order to evaluate blast problems and make modifications to round designs.

Jan 1, 1988

By Frank Wilder, Mark Ferrero

One of the challenges currently facing the explosives industry is how to transition its workforce and its business systems to respond to the increasing pressures for improved inventory and records management. The pressures applied by many U.S. federal and state agencies, such as the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and the Department of Environmental Protection (DEP), as well as regulatory agencies around the world, are increasing the need for accurate inventory accounting of explosive materials and blast documentation. With blasting companies now facing regular documentation audits, potential liability issues may arise due to the inconsistent or missing documentation.

Jan 1, 2006

By Peter Moser, G. Reihholf

Holcim, one of the world's leading suppliers of cement, aggregates and concrete, has set up a few years ago a working group “Quarry” in order to optimize the performance of its central European quarry operations in terms of work safety, environmental standards and economic performance. One of the activities of this working group "Quarry" addresses the subject of blast fragmentation in the quarries. A benchmark study of the blast work in all quarries has shown substantial differences for the various operations in terms of drill& blast costs. Especially big differences were found with respect to the drilling patterns as a function of the borehole diameters and with respect to the utilization of the borehole volume for charging the explosives.

Jan 1, 2006

By Sandra Penttinen

To assist blasting professionals with the creation, documentation, and appropriate methodology to standardize the data collection of the pre and post blast investigation process. Penttinen Associates will present a logical non-technical presentation focusing on: Why pre-blast surveys SAVE How to prepare for pre-blast inspections What to do in preparation of pre-blast inspections The creation of an industry standard all-inclusive pre-blast document Establishing pre-blast inspection operational standards Preserving the data.

Jan 1, 2001

By Qian (Ken) Liu, Remi Proulx

A large scale blast damage project was carried out over the past two years at INCO Ltd Manitoba Division co-funded by the Canada/Manitoba Mineral Development Agreement. The experiment was conducted at the T-3 Mine in two mining stopes with an experimental drift developed in the hanging-wall for the installation of monitoring instrumentation. The objective was to observe and subsequently to reduce ore dilution by monitoring the performance of blasts, the hanging wall movement, as well as the cavity of the open stopes.

Jan 1, 1995

Hello, everyone. Way back in 1965, Devine and others at the US Bureau of Mines showed that a presplit fracture plane did not affect vibration levels transmitted across the plane (RI 6695).

Jan 1, 2010

I attended a funeral in West Monroe, Louisiana, for one of the best powder peddlers I’ve ever known. He started work in 1948 for Dixie Dynamite, a seismograph explosive distributor. His first job was as a truck driver, then magazine keeper and then sales re p re s e n t a t i v e . When Dixie Dynamite quit, he acted as an explosives sales agent for sometime before moving on to Kansas to be a sales rep for a distributor there. We called him the “ragin cajun” long before James Carville came on the national scene messing up things. While he was born in G e o rgia, he was a Cajun at heart. I don’t believe the old saying, “Build a better mousetrap and the world will beat a path to your door.” To me, the best products in the world need to be sold. Two examples of this are the Beta system for TV and the Apple Macintosh computers. Beta is the best system but VHS took over because the Beta people fell down on the selling job. Windows 98 is Macintosh ‘86 but again the engineers were not salesmen. Marion “Johnny” Johnson who was buried only about a half mile from his first magazine site proved that good selling is good citizenship. He could have sold any firstclass product, for he wouldn’t tolerate inferior items, and made a successful career of it, but he chose dynamite and the industry benefited from his talents.

Jan 1, 2004