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By Neal Lee

Often the effects of wet boreholes are not taken into consideration when designing a blasting program to exhibit a certain amount of explosive energy per unit of rock such as design by powder factor, expressed in lbs./bcy (pounds explosives per bank cubic yard) or kg/bcm (kilograms per cubic meter), often the effects of wet holes are not considered. This paper examines different methods of loading wet holes and the effects they have on actual explosive quantities/unit of rock. In particular, we are looking at the amount of water trapped within the explosive column (bulk loading from the collar), or the annular space left void of explosives product around and between cartridges (wet-bags) with many of the current wet hole loading methods in use. We will focus on the effect this has on actual powder factor relative to “as designed” dry hole loading values, as well as the effect on performance of the explosives.

Jan 1, 2011

By Brian Lewis, Reinhold Daykin Schnell

Blasting specifications and guidelines are very important aspects of detailed project specifications covering any scope of work (SOW) that involves explosives and blasting procedures. A lot of larger construction or tunneling projects require some degree of project specifications for the entire scope of work on such project, including blasting specifications. It is important that all blasting specifications effectively and accurately address all explosives and blasting concerns associated with the SOW for such project. This includes safety and security, required personnel and their associated responsibilities, procedures and applications involving explosives, blast design and planning, blast monitoring and reporting, quality assurance and quality control, and local, state, and federal regulations and limitations. With the of wide range of information required in blasting and overall project specifications along with the risks associated with work involving explosives, it is also important to ensure qualified personnel are involved in interpreting or compiling and approving any blasting specifications and guidelines. The purpose of the following paper is to explore and present the basic information, as summarized above, that should be included and considered in the creation of detailed blasting specifications and guidelines. Detailed information is presented in specific relation to a potential bid package that would be compiled for a construction or tunneling project requiring protective or high-profile blasting.

Feb 6, 2023

By David Porter, Nathan Rouse

The implementation of presplit blasting has been widely utilized in open pit and underground tunneling. This case study works through the iterative process of developing a heading drill and blast design to control overbreak and limit backbreak in cut and fill headings. The initial design was based on rule of thumb parameters, and the design was then modified for the field conditions based on results. Throughout the design process the drill profile, explosive charge, and timing were modified to yield the best profile compared to design. Data collection during the design process was extensive to best understand the effect of modifying parameters, and gauge performance of design changes. Input from the miners as well as engineers was considered to allow for the best possible adaptation of the design change from existing practices. During the process resistance to change was realized and accounted for to understand the issues that the miners were facing and how to best address them while ensuring high quality blasting. Workforce buy- in was addressed by illustrating the long term benefits of higher quality blasting and the tradeoff of with a slightly more in depth drill and loading cycle.

Feb 6, 2023

By Gordon C. Petersen, Gary A. Almeraris

This paper describes the controlled blasting techniques required to mine a rock tunnel section of a main interceptor located in the Boston Metropolitan area. The 3m (10 ft) x 2.8m (9.25 ft) horseshoe shaped tunnel was driven 490m (1600 ft) by conventional drill and blast methods. The geology varied round by round and consisted of five highly faulted and jointed igneous rock types. The tunnel intersected numerous slickenslides and open mud seams which hampered both drilling and loading operations. Smooth blasting wee critical in order to keep overbreak tc a minimum in this extremely hard but blocky ground.

Jan 1, 1991

By Lifent Li, Jhon Silva-Castro

Since millisecond-delay detonators were first introduced, at least two variables, among others, have been more closely considered when timing a mining blast: the accuracy and the precision of the initiation system. Currently, most mine blast design software has the capability to use the precision/accuracy of the firing system and display the overlap timing window between charges in any given time interval (8 ms, 3 ms, etc.). Despite these technological advances, there are still situations which result in the overlapping of charge timings. The consequences of overlapping charges involve flyrock events, fragmentation and diggability problems, and other inconvenient situations affecting the operation of the mine.

Jan 1, 2015

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 John A. Davis, David W. Brunton

(Excerpts, pp 157-160) The usual means of firing blasting charges, especially in tunnels and adits in the Western States, is by the use of a safety fuse. The term safety fuse originated from the fact that when properly used under working conditions this fuse burns at a uniform rate and does not flash or explode, as was often the case with the means employed for igniting blasting charges previous to its invention; but the term is somewhat misleading, because the fuse is not, nor has it ever seriously been claimed to be, safe for use in gaseous coal mines. The fuse used for tunnel work is composed of a core of gunpowder surrounded by various layers of waterproofing material.

Jan 1, 2015

By Javier Illanes Pizarro, Gustavo Huerta Valer, Jorge Cárdenas Miranda

Bench stability is the basis of sustainability in an open pit mining operation. Taking care of the pit walls while maintaining fragmentation results can prove a challenge. In this study, technical proposals have been developed for extra hard rock mass (UCS>175MPa) with presence of unfavorable structural planes in high copper grade zones. The base case shows low compliance of fragmentation results and a significant loss in berm width, with over size boulders causing low primary crushing rates. Paradigms in current drill and blast design were overcome to improve fragmentation results and achieve objectives.

Feb 6, 2023

By Keith Henderson

An open pit quarry operation in West Central Illinois provided a challenging proposition regarding the removal of a rock wall that once separated two pits, but was now in the middle of the north wall of the combined pit. Their mining plan included the development of a new ramp into the quarry pit in order to lessen the slope and to shorten haul truck cycle time. The task would be to remove a section of rock left behind from mining operations more than 20 years ago that was at or near the bottom of the designed ramp.

Jan 1, 2012

By Charles D. Sutton

Safety is an important part of the everyday activity for the explosives industry. The overall accident experience has not been adverse, however, many insurance companies have eliminated coverage for explosive related activities. The Nobel Insurance Group has responded to this insurance problem for our explosives customers. It is vital that safety efforts continue for all aspects of the business. The continuation of insurance policies for explosives, clearly depends on safety.

Jan 1, 1987

By Douglas R. Burns

During the summer of 1989, Maine Drilling and Blasting of Gardiner, Maine was contracted by Cayer Corporation of Harvard, Massachusetts to drill and blast an interceptor trench at the Nyanza Chemical Superfund Site in Ashland, Massachusetts.

Jan 1, 1991

By David Porter, Nathan Rouse

The implementation of presplit perimeter control in underground mining as a method to decrease dilution yields positive benefits throughout the current and future mining cycles. A case study to understand the benefits of reducing overbreak and underbreak in a cut and fill mining cycle was performed to quantify the reduction in backbreak. The study was performed in a control section of the mine where a presplit perimeter control design was utilized for a length of heading. This control heading was then compared to the existing standard blasting design within the same mining zone. The comparison included multiple aspects of the mining advance including overbreak, dilution of waste, dilution of Cemented Rock Fill, bolt counts, and cycle times. Once mining in the control section was completed and mining commenced in adjacent headings, blast damage due to blast design could be quantified.

Feb 6, 2023

By N Gkikizas-Lampropoulis

Selection of delay times to optimize fragmentation has been a controversial topic among researchers and blasting practitioners. This paper interprets previous experimental information on the effect of delay on fragmentation with the aid of some new experimental observations of the time of detachment of the free face of the blast as well as results of numerical modelling. It was shown that detachment of the burden occurs at delays shorter than the one which produced optimum fragmentation in the experiments, suggesting some fragmentation improvement due to gas action. In addition, at the spacing to burden ratio of the experiments, the damage zone from an earlier detonating charge extends the distance to the neighboring charge, essentially affecting the burden of some of the holes of the blast, at detonation time. Computer modelling demonstrated that increased spacing results is less overlap of stress induced damage zones meaning that there is less influence of delay on stress wave induced fragmentation. It was also shown that simultaneous initiation results in less back break, while increased back break may result even with short delay times.

Jan 1, 2016

By Agne Rustan

The goal of this paper is to describe Fragblast 10 for those who did not have the opportunity to attend the Symposium and also give some examples of new research findings used in practise in some countries throughout the world. Also some entertainment events from the symposium are described.

Jan 1, 2013

By Regina Rocha, Miguel Humpire

One of the challenges within unitary mining operations is blasting, which has a significant downstream impact on the following processes, which is why mining companies ensure the results of the blasting process through joint work with explosives specialists’ companies.

Feb 6, 2023

By David Leidel

A revolution in hydrocarbon well completions within the last thirty years has enabled drillers to tap the resources of known gas plays in an economically viable manner and deliver to market natural gas supplies for industrial, transportation and domestic use without the importation of liquefied natural gas from verseas. An added benefit has been the convenient location of one of these gas plays, the Marcellus Shale, in the Northeastern states strategically close to a major natural gas market, namely the cities and towns of the New England and Mid-Atlantic states. As a sidelight, the development of the tight gas reservoirs and their subsequent production has created thousands of jobs in an otherwise lackluster economy.

Jan 1, 2014

By Dr. Paul Worsey, Dr. Calvin Konya, Dr. Anthony Konya

Development of methods to calculate presplit blasthole pressures through simplified models, namely the Empirical Model and the Detonation Pressure Model. These models can be used with variations in explosive type and diameter, along with borehole diameter. All models have been validated with test data and shown to have minimal error.

Feb 1, 2020

By Robert Hopler

After the disbanding of the Gunpowder Trust Association in 1904, the Association of Independent Powder and Dynamite Manufacturers was formed, followed in May of 1906 by the formation of the Association of Manufacturers of Powder and High Explosives. Due to a lack of success in attracting all manufacturers to membership, these organizations did not survive.

Jan 1, 2014

By William Everett, Jack Eloranta

United Taconite is an iron ore mine operated by Cleveland-Cliffs Inc (Cliffs) located near Eveleth, Minnesota. The mine, originally known as Eveleth Taconite Mines, was purchased in December 2003 by Cliffs (70%) and Laiwu Steel (30%). The mine site, known as the Thunderbird Mine, produces taconite ore for delivery by rail to the company’s Fairlane plant, located approximately 10 miles to the south near Forbes, Minnesota. At the plant, the crude ore is ground, concentrated and processed into pellets for steel industry customers. Total pellet production capacity is about 5.4 million long tons (Ltons) per year.

Jan 1, 2006

By Jason Baird, Joshua Hoffman, Phillip Mulligan

The purpose of this report is to address the method of reducing the overall explosive weight of Explosively Formed Projectiles (EFPs) while still achieving satisfactory performance. This reduction is crucial in order to comply with outdoor explosives testing standards for Missouri University of Science and Technology’s (Missouri S&T’s) Experimental Mine. Initial EFP design testing exceeded given limitations, making reliable data difficult to ascertain. EFPs must be tested outdoors to allow for specific information recordings which aid in defending against them.

Jan 1, 2010