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By James W. Reil, Douglas A. Anderson

Common wisdom has it that a blast which breaks rock efficiently should-generate less ground vibration. In practice, however, this idea has not been-rigorously tested. In a previous paper presented at an SEE meeting[1] we described a method for-controlling vibration using delays. The method is very effective in controlling-annoying low-frequency ground vibration. We noted that observed ground-vibration differs in some respects from that predicted by adding single-charge-waveforms.

Jan 1, 1988

By William Yutmeyer, Meredith Hardwick

Since 1996 there have been at least two teams formed within the U.S. Government to develop a consistent set of risk-based standards to be used to govern safety. The first of these was the Risk and Lethality Commonality Team which developed risk criteria associated with protecting personnel during launches at the national test ranges. The second team titled the Risk-Based Explosives Safety Criteria Team (RBESCT) is the subject of this paper.

Jan 1, 2007

By D. Scott Scovira, Rick Webber

The Iron Ore Company of Canada [IOC] is a global leader in Arctic mining applications, and the blasting crew have something to be very proud of. On Wednesday 21 Dec 2005 at 3:28 PM the largest single bench blast in the company history was detonated. The successful firing of this 5.0 million tonne [5.5 million ton] blast surpassed the previous company record of 3.8 million tonnes [4.18 million ton].

Jan 1, 2008

By Mark S. Stagg, Stephen A. Rholl

The Bureau of Mines is studying blast delay timing influences on rock fragmentation in a series of tests that started in 3-ft concrete blocks, progressed to 45in-bench reduced-scale tests in massive dolomite, and has now included 22-ft-bench full-scale tests in a thin-to-thick horizontally bedded dolomite. This paper discusses the full-scale test results and how they compared to the concrete block and reduced-scale studies.

Jan 1, 1988

By Salah A. Taqieddin

The blast casting technique of removing overburden is an innovative technique which was successfully used in the mining of certain surface coal and quarries. This method was found to be efficient in minimizing the labor and equipment cost while accelerating mining operation with safety. This method was successfully applied to horizontal as well as to dipping coal seams. Also it was practically applied to single as well as to multiple ore bodies

Jan 1, 1992

By John P. Ashby

Production blasting is a process of destruction of rock masses in order that ore may be extracted. Many open pit operations are faced with the apparently conflicting requirements of providing large quantities of fragmented rock for the processing plant and of minimizing the amount of damage inflicted upon the surrounding pit slopes. A reasonable compromise between these two conflicting demands may often be found by means of simple engineering of production blasts.

Jan 1, 1980

By Rob Grant, Manuel Lopez Cano, Mike Briggs, Ken Fletcher

The scorched desert sands and life giving waters of the River Nile in Egypt have been the back drop to awe inspiring engineering feats for over 4,700 years. The latest engineering marvel to grace the land of the Pharaohs is the Mubarak Pumping Station Project at Toshka. This ambitious project aims to open up an area of 607,000 hectares (1.5 million acres) of barren desert to irrigation based farming with the supply of 29 million tonnes (32 million tons) of water per day, drawn from Lake Nasser on the river Nile. It is anticipated that this currently unpopulated area of southern Egypt will soon flourish and become home to several million Egyptians who will conduct their lives around the water supplied by the 230 kilometers (144 miles) of concrete canals. An integral part of the pumping station is the intake canal. The canal was excavated in two sections – the dry excavation, and the wet excavation. The wet excavation comprised of some 5.5 million cubic meters (7.2 million cubic yards) of rock to be drilled, blasted, and excavated, from the surface of the lake. The challenge at hand was how to achieve this safely, quickly, and cost effectively, with water depths of up to 45 meters (148 feet), excavation depths of up to 47 meters (154 feet), blast production rate peaks of up to 30,000 bank cubic meters (39,200 bank cubic yards) per day, blistering summer air temperatures up to 60°C (140°F), and security concerns about the storage of large quantities of explosives in the Middle East region. The solutions to these challenges were engineered by UEE Explosives and centered around the use of a microgel bulk explosive called Rioflex™ and an international team of engineers and operators from three continents. The microgel and accompanying pumping system allowed pumping rates of up to 17,400 kg (38,400 lb) per day, and more importantly, enabled the bulk product to remain as an oxidizing matrix whilst in transport and storage, transforming into an explosive only moments before being pumped into the blastholes. This case study outlines the underwater drill and blast process employed at the Mubarak Pumping Station Project at Toshka, and the novel solutions to the unique challenges encountered.

Jan 1, 2004

By Jon Andrews

Purpose: To show how in managing risk in avalanche control blasting has changed throughout the years, and try to define the term “Acceptable Risk”. History: The history and the way we manage risk in avalanche control blasting to the avalanche control crews and public has change over the years dramatically. From the mid 1800s to about 1920 was the Risk vs. Rewards era, the Industrial Revolution. Now it is a Risk vs. Liability, the age of Liability.

Jan 1, 2009

By Jerry Bennett

A recant Bureau of Mines analysis has shown that failure of blast area security systems is the mayor cause of mine blasting accidents. Accidents occur during scheduled blasting because of failure to clear the blast zone, inadequate guarding, and failure of personnel to follow instructions, retreat to a safe location and/or take adequate cover. The high incidence of blastslte security-related accidents could be considerably reduced by increased attention to improving minesite blast-guarding practices.

Jan 1, 1984

By Todd B. Harrington, Dennis M. Lydon, Walter B. Sudweeks

Heavy ANFO products made by mixing ANFO (or AN prills) with a relatively small amount of emulsion (typically 15-30 percent) have become very popular in recent years. They are less expensive than straight, sensitized emulsion and maintain the good shooting characteristics of ANFO but have higher bulk strengths. Their use, however, is generally limited to larger diameter, dry boreholes. Smaller diameter, wet-hole quarries have not been able to widely utilize this low cost bulk product.

Jan 1, 1989

By Scott Giltner, Allan Koski

Blasting is one of the lowest cost yet most critical parts of the mining cycle. This paper discusses the findings of an audit conducted on the blasting operation at an iron ore mine. The purpose of the audit was to review current blasting practices in order to identify opportunities for production/cost improvements. The approach taken in the audit was to observe general blasting practices, their related downstream effects and to compare current procedures to established best practices.

Jan 1, 2009

By Scott E. Winston, Spencer C. Watson

Dynamite is a generic term for a variety of high explosive formulations containing a blend of liquid and solid nitrate esters co-mixed with solid oxidizers and carbonaceous fuels. Dynamites can be divided into general classes of nongelatins, semi-gelatins, and gelatins which vary as to their detonation rates, densities, and water resistance. There are also numerous products within each classification depending on their utilization or on their permissibility in various types of underground mining operations.

Jan 1, 1985

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 D Schneider, H Elliott

The advantages and disadvantages of using inclined boreholes in blasting has been under discussion for a long time. Some recognized disadvantages are that drilling costs, both operating and capital costs, are higher for inclined holes than for vertical ones, and that drilling accuracy is more difficult to maintain. People who have used angled holes in practice, on the other hand, have claimed that the quality of blast results was improved. In fact, their popularity has increased, especially in Australia.

Jan 1, 1988

By R C. Berglund

Since the Republic Mine began production in the mid 1950's, drilling and blasting practices have continually changed. In recent years, progress has been achieved through the development of more precise blast engineering methods, in greatly increasing the use of non-water resistant ammonium nitrate explosives, and in changing to a non-electric in-hole delay initiation system. Also, recent experience indicates that ammonium nitrate fueled with nitropropane and methanol is a viable substitute for aluminized AN-FO.

Jan 1, 1980

By C A. "Hawk" Hanger

"The paper that will be presented is an in-depth study of sequential blasting using standardnon-electric shock tube down hole timing along with surface M.S. connector timing.Included also will be a discussion on the advantages in fragmentation, digability, oredilution' and ground vibration versus the common practice of row by row blasting. Alongwith the written presentation, several visual illustrations will be included. The visuals willrefine the actual direction and predicted movement of the shot involved."

Jan 1, 1993

By Clarence Zink

Aside from the mechanical properties and process of actual rock breakage, rotary drill bit performance is affected by several “post breakage” items: cuttings size, flushing air pressure, flushing air volume, cuttings load, drill hole geometry, etc. We all recognize that more efficient drilling creates bigger cuttings, more air pressure cleans the hole bottom better, more air clears the cuttings from the hole, and a better hole geometry allows cuttings to escape with a minimum of “regrind”.

Jan 1, 2006

By Gimtong Teowee

SDI has launched the Electronic Detonator Blasting System containing a set of robust serial protocol and hardware exhibiting great ease in field usability and deployment. Programmable delay time with increments of 1 ms up to 10s is possible with excellent timing accuracy. Bus length of up to 2 km containing 1600 EIMs can be employed. A key feature of the SDI Electronic Blasting System has been its high tolerance towards current leakage in the bus line.

Jan 1, 2007

By Cameron McKenzie

Flyrock is a complex issue involving interaction between the charging crew, the blast design, and the local geology, and once conditions on the shot meet certain criteria, the probability of a flyrock incident becomes unacceptably high. It is essential that flyrock awareness be built into the blast design process, requiring an engineering approach to understanding and controlling the outcomes and managing the associated risks. Based on previous studies of flyrock and published literature relating to fragment motion at high velocity in air, the equations to predict maximum flyrock range, and the size of particle achieving the maximum range, for blasts of varying rock density, hole diameter, explosive density, and state of confinement have been developed. These equations, and other associated correlations, permit the flyrock footprints to be established for any charge configuration, in any size blasthole, in rock of any density, and with particles of any known shape factor. The equations developed, and the mechanisms they reflect, allow engineers to go a long way towards understanding the primary factors controlling flyrock generation, including the rock mass, the blast design, and the quality of blast design implementation, i.e. the human factor. The paper presents guidelines as regards use of the equations to establish personnel clearance distances as a function of charge design and implementation, and equations to estimate appropriate stemming lengths when blasting must be conducted close to occupied or sensitive structures. The equations are amenable to definition of, and quantification of Flyrock Risk.

Jan 1, 2009

By Joel Warneke, Cristian Caceres, Ed Mchugh

NIOSH researchers collected basic data from two blast rounds at the SSX-Steer Mine as a component of a larger study on controlled blasting, the goal of which is to reduce injuries from falling rocks in underground mines. Drilling and blasting procedures at the mine were observed. Rock mass property data were collected, a program of seismic monitoring and analysis was conducted, and 3-D laser survey scans of the workings before and after each blast were performed. The geologic data showed that the rock mass quality was characterized as poor to very poor. It was essentially uniform within the panels examined. The recorded seismic data indicated that fill material acted as an effective damper to seismic energy. The pre- and post-blast laser scans showed both over-break and under-break conditions, highlighting the problems associated with blasting a weak rock mass. By comparing the achieved results to the intended design, potential improvements in the drilling and blasting practices can be identified. Comparison of these data with similar data from other mines will help define how various combinations of rock and fill behave during blasting. Through studies such as these, data collection procedures and analysis techniques can be refined. An ultimate goal is to develop blast procedures tied to rock mass characteristics that can minimize damage to rock in the perimeter of the opening, limiting the amount of loose rock and improving the safety of miners.

Jan 1, 2008