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By Paul Worsey, Ron Ecklecamp, Scott G. Giltner, Ronnie Inman, Terry Drechsler

A blast monitoring program conducted at Chemical Lie Company’s new lime calcining facility near Ste. Genevieve, Missouri is discussed. The purpose was to develop blasting criteria for the construction and operation of the lime plant within the quarry operated by Tower Rock Stone. Further, it was imperative to accommodate production requirements into the blasting criteria. The major concern was the effect of blasting on the curing of green concrete during the construction of the storage silos and kiln stacks. In addition to discussing the susceptibility of curing concrete to blast vibrations, the paper also details how this varies with time.

Jan 1, 1996

By Piet Halliday, Ellina Kharatyan

Conventionally, emulsion matrices (unsensitized) need to be sensitized to become detonable explosives. This is done either chemically or mechanically. Both methods have their advantages and disadvantages. Mechanical sensitization involves the addition of microballoons (plastic or glass) to the emulsion matrix, in order to create hot spots during detonation. This is usually done at the manufacturing site and poses a safety risk in terms of the storage, transportation and handling of a 1.1 type explosive. Many countries throughout the world make use of chemical sensitization as opposed to mechanical sensitization as this allows for the storage, handling and transportation of two 5.1 type products rather than the 1.1 type explosive. Chemical sensitization involves the addition of a small amount of a chemical that reacts with a component of the emulsion matrix causing the formation of gas bubbles that act as hot spots during detonation. The disadvantage of this is the lack of accurate density control (due to various factors affecting the reaction) and the lack of comprehensive understanding of the operators of the reaction. This can easily result in poor blast performance. Due to these disadvantages a pumpable, non-detonable (5.1 type) mechanical sensitizer was researched and developed. This product allows for pumping at a 50:50 volume ratio with the emulsion matrix, when loading into blast holes. The significance of this is that a 1.1 type explosive is formed in the blast hole. As such, the security and logistical issues of the transportation and storage of the 1.1 type explosive are eliminated. Another advantage is accurate density control of the final product, specifically in small diameter long hole applications. A cost effective, unique mini pumping system has been developed for the loading of this product. Moreover, this system can easily be used for secondary blasting applications and the on-site packaging of cartridged explosive products.

Jan 1, 2015

By Walt Meglasson

The Kaiser Aluminum Company Smelter, one of several in the Pacific Northwest, was built in 1942 and operated by the Olin Company during World War II and then purchased by Kaiser Aluminum after the war. At its height, the facility employed over 350 workers and was capable of producing 73,000 tons of aluminum per year. It was closed in 2000 through a combination of rising electrical and labor costs, and the inability to compete with more up-to-date foreign facilities.

Jan 1, 2008

By Joshua Hoffman, Rob Farnfield, Catherine Johnson, Braden Lusk, Morgan Lane

IMESAFR (IME Safety Analysis for Risk) is a quantitative risk assessment software tool developed by the Institute of Makers of Explosives (IME) and A-P-T Research, Inc. It is used for managing risk in the commercial explosives industry, the newest version of the software was completed in 2012. This paper discusses the use of this software package in conjunction with data collected for a television series on the reenactment of the ‘London Blitz’, a 57-day bombing of the City of London in 1940. In this reenactment, purpose built structures using period design and materials were constructed at a test facility in the North of England. Five devices ranging in size from 20 kg (44 lb) to 1100 kg (2400 lb) were detonated at varying distances from the structures; each blast was monitored by EPC-UK and the resulting structural damage was analyzed. Data recorded from the blasts included high-speed videos, photographs before and after each event and air overpressure readings. The same data was inputted into the IMESAFR software package to assess the risk imposed on the residents of London during this time. The appropriateness of this tool for evaluating structures built using historical practices is discussed. Data from the full scale tests is compared to effects predicted by IMESAFR. Further analysis of the risk recommendations produced by IMESAFR is compared to the actual damage assessed during the large scale tests.

Jan 1, 2014

By C. T. Aimone-Martin, V. L. Rosenhaim

The response of two structures to blast-induced ground vibrations were evaluated and compared in order to quantify the impact of different blasting operations, hard rock and soft rock blasting, upon the structures movements. The first instrumented structure was a residential type, located in the operational area of a coal mine, were blasting is conducted in soft rocks, such as siltstone and coal, with compressive strength ranging from 20 to 50 MPa. Blasting is characterized by low benches, with hole lengths averaging 5.5 m (18 ft) and low powder factors, 140 to 210 g/m3 (0.236 to 0.354 lb/yd3), resulting in very little horizontal movement of the rock during the blast. The second structure was a commercial building, located in a basalt quarry (compressive strength between 109 and 180 MPa), where blasting is conducted in 12 m (39.4 ft) benches with powder factors ranging from 200 to 350 g/m3 (0.337 to 0.590 lb/yd3). Velocity sensors were placed on the structure walls to measure wall displacements and calculate blast-induced strains in the walls, and these results were compared with the driving ground excitations. The calculated strains were compared with the limits of rupture of the cement grout used as mortar between bricks and as wall coating, considered to be the weakest material in the structure composition. The blast-induced response of existing cracks in the structures were also measured using displacement gages and compared to the daily influence of weather fluctuations, such as changes in temperature and humidity, on crack movement. The results show that for the same levels of ground motions the structures present different movement, resulting in distinct levels of induced strains on the walls depending on the geology. The influence of long-term temperature and humidity variations on crack movements on both structures is very similar, during the same seasons of the year. Crack response to long-term weather changes is 2.5 to 3.5 times greater than blast influences.

Jan 1, 2015

By Tapan Goswami, Brent Geoff

Mining multiple steeply sloping coal seams introduces challenges in terms of safety and productivity. Work on steeply sloping surfaces for the processes of bench preparation, mark-out, drilling, loading and blast tie-up, coal cleaning and recovery is inherently hazardous. Furthermore, a large number of mining cycles is usually necessary, as small rounds are required and each layer is separately drilled, loaded, blasted and excavated. This exposes personnel and machines to additional risks and also incurs higher unit costs of mining as machine productivity is reduced. A case study is presented of a mine in New South Wales, Australia where three coal seams are separated by layers of inter-burden rock. Due to the unfavourable sloping nature of the coal seams the conventional practice was to drill and blast each layer separately.

Jan 1, 2010

By Dyno Nobel

Impact of Enhanced Security on Operations Budgeting - What is the “value” I receive for enhanced security? Is there a “return” for the money I spend? Regulatory driven Economic driven

Jan 1, 2006

By Ewan Selers, Gary Cavanough

Drilling automation technology is well advanced and automated drill rigs are in use at a number of operating mines. This is not the case for the other drill and blast processes due to significant technical challenges to overcome. These challenges, with regard to the current “on bench” practices, include placing the initiators, loading the explosive and connecting up the initiation system. Although difficult, these challenges will be solved with engineering advances.

Jan 1, 2016

By John Floyd, Maria Rocha, Benjamin Cebrian

Wall control blasting is needed in most metal mining operations in terms of increasing mineral reserves and assuring the safety of the operation. This type of blasting has the goal to achieve a clean, stable rock wall in the shortest distance from a well fragmented, easy to excavate, blasted rock mass. This can be done with a variety of blasting techniques, all of which decrease the explosive energy towards the final wall. Each technique needs to suit the geology: modified production blasting, buffer blasting, pre-split and line drilling of empty holes. Pre-split is the most expensive technique, and allows final steeper bench face angles while modified production blasting is the least expensive but needs wider berms.

Jan 1, 2018

By E. Líder, J. Pavez, J. Rivera

The application of new technologies, methodologies, and the use of new products in mining operations is a practice that is becoming more common in the industry every day, added to the new challenges and restrictions found in the operation. In the city of Tierra Amarilla, the interaction between mining operations and the community presents a constant challenge given the proximity to the community and the limitations that this presents. Explosive charge mass, in conventional blasting using traditional explosives (ANFOs, packaged explosives for example) limits the explosive charge lengths (they are reduced), impacting the explosive charge productivity. To improve the productivity of explosive charge and fragmentation, the use of low-density explosives was proposed, allowing the increase of the explosive charge length, trying to maintain the vibration levels within the established limits (2mm/s), preserving the fragmentation of the rock in the required sizes. The present study shows the results obtained from the application of low-density bulk emulsion for production blasting charges using upward and downward fan drillings. During this process, 18 blasting events were carried out, of which 8 were Up-hole loading (average density of 0.75 gr/cc) and 10 with Down-Hole loading (average density of 0.95 gr/cc). In summary, a total of 110,760 tons of ore have been broken, using low density emulsion, meeting the proposed objectives such as: 33% reduction of vibrations, 12% overbreak (within the theoretical design), P80 of 11in and 4.6% in fines.

Jan 1, 2024

By Scott G. Giltner, Terry Millar, Ben Bringhurst

"Kennecott Utah Copper (KUC) Smelter scheduled a rebuild of their flash smelting furnace forSeptember, 2014. KUC’s goal in this project was to reduce the rebuild time from 65 to 55 days by using explosives to break the matte and brick layers of the uptake shaft and hearth sections of the furnace. Previous rebuilds had employed the slower technique of mechanical breakers to remove the matte and brick layers which took 22 days. KUC has many years of experience in removing slag from the uptake shaft, but they had never used explosives to remove the hearth. As far as KUC was aware, no other smelter operation had attempted a hearth removal in this way."

Jan 1, 2016

By Gary Cavanough

The spontaneous exothermic reaction of ammonium nitrate explosives with sulphide-containing rocks, commonly referred to as reactive ground, is a site-specific condition that can lead to spontaneous detonations. Mine sites typically carry out regular assessment of ground for reactivity. In Australia, reactive ground testing is conducted according to the Australasian Explosives Industry Safety Group (AEISG) Code of Practice. This paper presents a new method to assess reactive ground. The new method can be completed on the mine site or in the laboratory. The new method allows samples to be tested in hours not weeks, as required when using the method prescribed in the AEISG Code of Practice. The new method also provides an explanation of why ground is reactive or not reactive, Whereas the AEISG Code of Practice provides a reactive, not reactive or marginal results with no understanding of reason for these results. Case studies on the use of weathering agents, pH, sulphide content and carbonate content will be reported. These case studies identify instances where the testing as per the AEISG Code of Practice provides false positive and false negative results. A false positive result will require the use of inhibited products when they are not actually required which increases costs and reduces productivity due to the need to used multiple explosive products. A false negative result increases the risk of an unplanned initiation of a blast hole.

Feb 6, 2023

By Gregory B. Poole

Data collected with 16K sampling at a variety of blasting sites (construction, quarry, trench, mine) and monitoring locations was analyzed to effectively show the 16 different 1K readings all based on the microsecond that the unit went into monitoring.

Feb 1, 2020

By K. Best, D. Conn

The US Army Corps of Engineers KY Lock Project in western Kentucky presented the blasters and vibration consultants with a set of unique challenges. The blasters on this project were faced with difficult geology and joint set orientation and sequencing of blasts opposite from what the explosive engineer/blasting specialist had recommended. Combining these issues with strict vibration and air overpressure specifications, blasting as close as 7 feet (2.1 meters) from a new lock wall, site topography that influenced the air overpressure, limitations on seismograph geophone placement that led to anomalies in seismograph recordings; surprising lessons were learned by everyone involved in the project and it is the authors’ goal to share this valuable information with everyone in the blasting industry.

Jan 1, 2024

By Alexandra Yuyali

The objective of this research work is to increase the drilling ratio represented in tons per drilled meter (ton/m) to reduce mining costs. One of the key characteristics of this research is the use of the ITH (in-the-hole) drilling rig with a water-powered hammer, also known as Wassara™. The patented Wassara™ in-the-hole hammer is powered by high-pressure water instead of air. To reach the objective, a new design of the blast pattern was implemented considering the following: Burden from 1.7 m (5.6 ft) to 2.8 m (9.2 ft) Spacing from 1.7 m (5.6 ft) to 2.7 m (8.9 ft) Drill diameter from 89 mm (3.5”) to 102 mm (4”) Drilling length from 15 m (49 ft) to 30 m (98 ft) Borehole deviation < 2% The result of this new design is the optimization of the drilling ratio (ton/m); having as a baseline 5.2 ton/m with traditional equipment and obtaining 13.7 ton/m with the ITH drilling, which generates annual savings of $2.43M.

Jan 21, 2025

By Stephen Mansfield, Saran Sankar

The Sentinel open pit copper mine, operated by First Quantum Minerals Ltd, is located in the North West province of Zambia. The Sentinel orebody is a sediment-hosted, structurally modified deposit in which mineralisation is contained in the phyllite formation, which occurs as a series of layered, continuous sheets having a northerly 20 to 30⁰ dip. The persistent nature of the geological structure can lead to the generation of large slabs when joints are relatively close together or very large blocks when joints are more widely spaced. With standard blasting methodologies, the challenging fragmentation most commonly occurs in the stemming zone and blast interfaces, reducing excavation rates and increasing the risk of crusher bridging events and reduced throughput. A generalised approach to increase powder factor would increase in drill and blast costs and would not be sufficient to target the specific cause of the challenging fragmentation. Implementing differential blast energy based on post blast requirements for different material type, such as ore and waste, and rock mass characteristics is not new in the mining industry. High-energy blasts for ore aim to produce finer materials, enhancing downstream processes such as crushing and grinding, while reducing power consumption and increasing throughput. Conversely, waste rock often requires less energy in order to deliver optimised fragmentation for loading and hauling efficiency. Identifying and applying optimum blast energy to specific material type and geological domains will not only ensure smoother and efficient operations throughout downstream processes, but will have a direct impact on overall profitability of the entire operation. This paper will describe the methods used to model and implement differential blasting across a range of material types in order to deliver the required blast outcomes for ore and waste and the impact on downstream processes and drill and blast unit cost.

Jan 21, 2025

By Gerard McAlinden, Daniel Frost, Patrick McAlinden, James McAlinden

In an effort to recover Polychlorinated biphenyls (PCB’s) that had leached into bedrock below the Hudson River in Upstate New York, a shaft and tunnel complex was designed that would allow installation of inclined and vertical wells into the zones of contamination to recover PCB’s by gravity. A joint venture of Merco Inc., of Lebanon, NJ, and Obayashi Corporation, of San Francisco, CA, was awarded the contract for constructing the first Tunnel Drain Collection System in the world. Conventional drill and blast techniques were the most economical method to construct the project but due to the presence of PCB’s and community concerns, innovative drill and blast practices were needed.

Jan 1, 2010

By Andreas Gaich

A new 3D fragmentation analysis method for muck piles is presented. It works with aerial imagery from UAVs (drones) and handles entire muck piles with minimum user intervention.

Feb 1, 2020

By Paulo Couceiro, Manuel Lopez Cano

"The Panama Canal is one of the most important engineering projects of the modern era and plays astrategic role in the global economy and international maritime trade since its inauguration in 1914. Now, a little more than one century later, the final phase of its expansion program, the largest infrastructure works undertaken since its inauguration, has concluded. This expansion program has created a new lane of traffic along the Canal with the construction of a new set of locks – one on the Pacific side and another one on the Atlantic side -, increasing the Canal’s capacity and its impact on the world’s economy even more."

Jan 1, 2017

By Raphael Trousselle, William Reisz

The blasting industry is now well into its second decade of commercial use of electronic detonators. As an increasing number of blasters are introduced to the technology, the benefits are becoming more widely monitored and accepted in many surface blasting operations. However, their use in underground applications is not yet as widely established. This is primarily due to the distinct cost dynamics and processes associated with underground lasting.

Jan 1, 2012