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By Norman Paley, Zachary Pickett

The Red Dog Mine is a high-grade zinc-lead mine located in northwest Alaska which began operations in November 1989. In June 2014 the upper half of a charge in a trim shot in the Aqqaluk pit deflagrated. No other holes in the area were observed to react and the remainder of the pattern was shot without incident. This was the only known case of a deflagration in the 25 years of operations. As part of the investigation into the cause of this incident rock samples were obtained from the area of this hole and from other areas in this pit. The samples were assayed and tested for reactivity using the Reactive Ground Catalyzed Adiabatic test. Approximately half of the samples were found to be reactive with standard blasting agents. Unexpectedly, some of these were found to be reactive with blasting agents doped with urea to act as an inhibiter. Relationships between element grades and reactivity and between Specific Heating Capacity and reactivity were developed; however, the small sample size led to these models having an unrealistically large number of geological model blocks tagged as reactive. A program to better understand the behavior by testing more samples was initiated. Drill core was selected based on the predicted level of reactivity using the aforementioned relationships. The samples covered a greater range of grades and lithologies and included rock from the soon to be developed Qanaiyaq pit. The samples were dry pulverized then split for elemental assay, Reactive Ground Catalyzed Adiabatic testing, Specific Heating Capacity (SHC) determination, and X-ray Diffraction (XRD) mineralogical analysis. From this data, a Red Dog Mine specific assay based classification for separating reactive from non-reactive ground was developed. Furthermore, it was possible to divide the reactive ground into two subgroups: i) rock which reacts with ANFO-emulsion blends even when manufactured specifically with a reactivity suppression agent like urea and ii) rock which reacts with ordinary ANFO-emulsion blends only when a reactivity suppression agent like urea is absent.

By Abdel Rahman, M. Khaled, Abo Makarem

There are four large limestone quarries, located nearby Cairo metropolitan. Drilling and blasting operations are used to extract limestone for the cement industries. In these quarries, the blast vibration should be kept below a certain limit. One of these quarries is Tourah Portland Cement Company (TPCC) limestone quarry which, lies near important and historical large caves, within Tourah Mountain. Therefore, control of blast vibration level becomes very critical.

Jan 1, 2007

By Harry Verakis

Flyrock is the second leading cause of all blasting related injuries in surface coal, metal and nonmetal mining operations. It is also a primary cause of property damage, monetary losses and “near misses.” For the period 1978 to 2008 flyrock accounted for 11.6 percent of all blasting-related injuries in surface coal, metal, and nonmetal mines. A large amount of published material has been published on the safety hazard of flyrock, on ways to predict how far rock will travel from a blast, as well as ways to protect mine personnel and neighbors from flyrock. However, flyrock incidents continue to occur resulting in fatalities and “near misses” that could have caused fatalities. It was only good fortune in some instances that no one was in the mine's parking lot or other unprotected area when flyrock rained down or in harm’s way when a large rock punched a hole in the roof of a building or other structure.

Jan 1, 2011

By John Babcock, Bryan C. Smith

In a partnership between Luck Stone Corporation and Loudoun Water, a 42” (1.067m) steel pipeline was constructed along the perimeter of an extensive permitted reserve of diabase rock Luck Stone was about to begin mining. Loudoun Water provides drinking water and wastewater services to over 75,000 households in Loudoun County, Virginia. In discussions to establish the 30-foot (9.1 meter) easement for Loudoun Water within the permitted reserve of diabase rock, Luck Stone and Loudoun Water agreed on the following basic conditions: • Luck Stone could execute production blasting as close to the easement as physical conditions of overburden depth permits. We estimated the minimum distance to be about 75-feet (22.86 meters) from the centerline of the pipe. • Loudoun Water would install strain gauges on the pipe every 500-feet (152.4 m) along the entire length of the future reserve area. This resulted in the installation of 18 strain gauges. • Luck Stone would contract a third-party vibration monitoring company, agreed to by Loudoun Water, to monitor the strain gauges and provide seismograph reading at appropriate locations along the pipe as mining progresses. All information would be provided to Loudoun Water. • Luck Stone’s blasting will be conducted in a manner that ensures the recommended strains are not exceeded.

Jan 1, 2019

By Robert Hopler

The literature of explosives and blasting consists of a great variety of printed materials. These materials include technical papers, books, and articles by individuals and organizations; manufacturer’s product catalogs and brochures; handbooks offering guidance for the field blaster; complete encyclopedias on the subjects, and short entries in general-interest encyclopedias; government publications; proceedings of organizations devoted to the subjects; magazines specific to the subjects; articles in general circulation magazines; and other miscellaneous sources. In short, there is a multitude of literature on the subject, some well indexed for retrieval, but most not. This presentation will be a broad-brush look at some of the most important or interesting literature on the subject, since in no way can all the various references be mentioned, much less covered in depth. To illustrate the presentation, interesting materials from the author’s collection will be shown.

Jan 1, 2000

By George E. McCormack

At the time of my visit to the Peoples Republic of China I was employed by the E.I. DuPont Company as a Technical Specialist in the Explosives Department. The purpose of my visit was to observe the use of explosives in mining and tunneling in a coal field 500 miles south of Peking near Hsu Chou in Kiang Su Province. The DuPont Company was preparing a proposal for the sale of a Tovex water gel plant to the Chinese Government.

Jan 1, 1982

By Des Bolton

With the introduction of Cast Blasting techniques, field controls of Drilling & Blasting operations became more important. New drills were purchased which were equipped with sophisticated instrumentation and more accurate drilling plans were required. Concurrently a decision had to be made on the replacement of borehole logging equipment owned by the mine. The use of a contractor to log blast boreholes was eventually decided upon, the information gained from this operation is used in the short-term drill and blast planning and may also be used to assist in the coaling operation if density I quality correlations prove acceptable.

Jan 1, 1994

By J P. Tidman

The problem of blasting fragmentation has received a good deal of attention in recent years. Progress by the scientific method requires a good set of experimental data as a benchmark to test models. Recent models have become so complex that it is not possible to use the results of field data because the complete set of parameters needed to describe the rock and/or explosive are not available.

Jan 1, 1991

By G. Hames, A. Drake, B. Sampson

The Timbarra opencut gold mine is located about 30 km(19 miles) southeast of Tenterfield in northern NSW some 4 hours by car from Brisbane, the capital city of Queensland in Australia. It was a small operation designed to produce about 40000 ounces of gold per annum utilising contract mining and company owned crushing plant feeding heap leach pads. This is a standard setup except that the mine owner was in charge of all aspects of drill & blast design even though a contract drilling & blasting (shotfiring) service was being provided. The major problem was that the blasting operations were yielding massive amounts of oversize due to the jointed partially weathered nature of the granite. This was adversely affecting all downstream aspects of the operation as well reducing gold output as ore boulders were being dozed over the side of the mine as they were impinging on mining productivity. The oversize problem had to be solved as the mine was struggling to achieve design gold output. Significant design & trialing effort using minesite resources were utilised to reduce the oversize but this failed even when powder factors up to 1kg/bcm(1.68lb/yd) were used. Dyno Consult from Dyno Nobel were therefore called to investigate, review & trial options to reduce oversize from the top flitch.

Jan 1, 2003

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 Manuel Calderón

Chile is responsible for 30% of the global copper production; the world ́s largest. However, significant challenges are faced in this industry; declining grades (1.13% in 2002 to 0.61% in 2015), high cost of energy, scarcity of water, and environmental concerns. Mining trends suggest the future of the industry will be focused in the underground space, specifically due to the depletion of economically viable surface mineral deposits. For example, the largest block cave mineat Codelco ́s Chuquicamata mine is expected to reduce energy costs by 50% and dust emissions by 97%compared to the open cut mine. To access these underground deposits, critical infrastructure is required; horizontal tunnel developments, extraction levels, vertical raises, and ore passes with the on-time delivery of the highest quality outcomes being a requisite for successful project delivery (Lift 1 of 3 at Chuquicamata Underground has over 1000drawbells).One aspect that makes this scenario even more challenging for deeper underground operations is the increased risk profile (people, equipment, and geotechnical) that forms part of the general environment. Furthermore geotechnical risks should be considered and they include rock burst and windblast. The safe interaction with this environment must be sustainable throughout the full life of the project. This paper presents the Enaex group approach to addressing the blasting challenges and outlines the solutions created. Aspects such as rock mass damage occurrence as a function of blast vibration frequency content has been studied, as well as the development of blasting methodologies for guaranteeing the full 100% extraction of all infrastructure blasts, including the all-important draw bell volumes. The development of such infrastructure volumes in one single event using electronic detonators and the associated achievement of ambitious productivity goals, are described as a critical part of the successful construction of one of the most ambitious UG projects currently present on the world.

By Steve Colburn

The CRITERION Survey Systems utilize both theodolite mounted and hand held reflectorless distance meters. These are eye safe, easy-to-use, and specifically designed to endure the harsh environments characteristic to the mining, quarry and explosives industries. Survey data collected by the systems is digitally stored in a ruggedized data collector and then processed with a specialized, Windows-based, interactive software program which can be run on any standard PC.

Jan 1, 1997

By Alan Hooper

This paper and slide presentation is a brief rundown on what is probably the worst natural devastation I have ever witnessed. The epicenter of the quake that so violently shook Mexico City occurred 230 miles away near Mexico's west coast. The first calculation placed the quake at 7.8 on the Richter scale. This was later upgraded to 8.1. Each unit increase on the Richter scale indicates about a 30 fold increase in energy released. The quake was felt in much of Mexico and south Texas and damage occurred in many other Mexican cities. On the morning of September 19, 1985, at 7:18 A.M., the ground went into motion and shook for approximately 2 to 4 minutes. During this period most of the devastation occurred. At 7:38 P.M. the following day, the second quake hit and more buildings fell from this 7.5 quake. The ground in Mexico City moves like jello since it is a dry lake bed 7,350 feet above sea level.\

Jan 1, 1986

By J R. "Dick" Daniel

In the fall of 1988, The Cannon mine decided to investigate a central blasting system based on conventional electric blasting detonators being used to initiate rounds primed with Nonel detonators. The advantages of this hybrid detonator system were viewed as being safety and cost effectiveness. A study was done reviewing the safety aspects of utilizing a permanent blasting line installed throughout the main haulage drifts to a central blasting station located at the mine portal. The study addressed the following potential safety hazards: radio frequency induced current, stray current from both electrical utilities and transmission lines, galvanic and electrostatic sources of extraneous current.

Jan 1, 1989

By TA Louw, Dr CM Lownds

In an era where profits are constantly being eroded, mines are looking towards technology developments to assist them in solving mining problems and reducing mining costs. An emerging technology that could assist mines in becoming more cost effective is electronic detonators. Electronic detonators have been under development for several years. Over the past three years, the spotlight has fallen on commercial use of electronic detonators and the extent to which the promise of precise and programmable timing can assist mines with their environmental and productivity problems. This paper uses case studies to demonstrate both surface and underground applications where electronic detonators and blasting systems were used to solve typical mining problems such as vibration and fragmentation. Safety aspects such as hanging wall conditions and high wall stability also benefited from the use of electronic detonators. The paper also demonstrates how the use of accurate electronic detonators and blasting systems has resulted in improved/more even fragmentation with further downstream efficiencies. These efficiencies may include increased cast percentages, reduced oversized rocks, quicker cleaning times and increased production rates.

Jan 1, 2004

By Jeffrey N. Deisher, H Y. Fang, Richard P. Scheller, Robert M. Koerner

The need to adequately quantify cracking in structures in the vicinity of blasting activity becomes more important each year. This urgency comes about through a growing number of complaints and lawsuits between the various parties involved, i.e., operator/owner, government, and complaintant. It is felt that existing rules and regulations (mainly based on peak particle velocity of the soil or rock adjacent to the structure in question) fall short of such quantification and lead to confusion in adequately assessing structural damage.

Jan 1, 1977

By Curtis G. Kremer

"New explosives initiation systems continue to be developed as new technologies make advancements possible. Due to recent initiator developments, explosives users now have the most reliable, accurate, safest and easy to use systems ever offered. Three initiation systems recentlyintroduced which offer significant improvement over standard electric and nonelectric initiation systems include Magnadet, EXEL high-strength shock tube, and Redundant two-Dath surface delay systems. These three systems will be discussed zn cecail with rmpiasis on their functioning, safety characteristics, ani specific application areas."

Jan 1, 1991

By Masanobu Morita, Koichi Kurokana, Kenji Hashimoto, Yoji Tasaki, Yukio Iida

"It has been the long desire of blasting engineer to realize the automatization of tunnelblasting to improve the safety and efficiency. As for bore hole drilling, the automatizationhas been achieved by the improvement of drilling machine. However, the firing process isstill depending on the hand-operation. We developed the wireless initiating system using amacrowave power as a step for automatization of tunnel blasting operation. In this paper,we present the outline of the wireless initiating system and the results of experimentalstudy of the wireless detonator which is key component of the system."

Jan 1, 1993

By Donelson A. Robertson

Proper coupling between the seismograph transducer and the surface is the most important aspect of seismograph monitoring but probably receives the least attention in many blasting situations. Without good coupling, particle velocity measurements may be higher than actual and frequencies may be lower. If the field data are inaccurate, sophisticated instrumentation and computer programs cannot correct the readings.

Jan 1, 1993

By D. Bartley, R. McClure, W. Reisz

Ever since the 8ms criterion was developed in the early 60’s there has been an ongoing debate among many blasters as to its actual value in controlling ground vibration. The perpetuation of the myth surrounding the 8ms window can be partly attributed to its simplicity and convenience as a means for regulatory compliance. Unfortunately, the mindset that many blasters have adopted has hindered the development and use of more effective techniques and in many cases can actually be counter productive to vibration control.

Jan 1, 2006