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By C. Feliciano, M. Cavalcante

A large iron ore open pit mine in Brazil operates with reduced blast sizes, due to the imminence of red alerts in the rainy season and the proximity of plant and dam structures that demand control of the maximum load of fired explosives. Blasts are currently not allowed to remain loaded with explosives due to the risk of red alerts, limiting mine operations close to them. There is a need to increase the blast sizes, reducing the number of events required to obtain the planned mass and, consequently, the unproductive operating hours lost with mine evacuations. The WebGen™ wireless electronic initiation system is a technology for firing detonators via lowfrequency magnetic induction that propagates through the medium, without physical connection. A blast was carried out with 406 holes divided into 4 panels, aiming to validate the preloading technique with wireless detonators and its performance in safety and productivity. The absence of lead wires in the system eliminates the risk of interaction between vehicles and detonator cables in stemming and loading operations, which can result in unplanned detonation or misfire. By eliminating the need for a spotter, it reduces people's exposure to dust and the risk of human-machine interaction. Furthermore, it eliminates the risk of unplanned detonation caused by lightning strikes. The pre-loading technique with wireless detonators enables flexibility and efficiency in planning through temporary accesses over loaded areas. In the demonstration, driving over the loaded area was essential to avoid jams and excessive wear on equipment due to the narrow berm and very friable material. Another gain in productivity was optimizing operational stages, since detonators were programmed in parallel with loading, anticipating process stages, in addition to eliminating the need to connect detonators. Considering the average handling and savings in downtime due to the reduction of blasting events, a potential increase in movement of 49,000t (54,013 short tons) in 3 months was estimated, keeping the vibration results within the required limit. The trial with wireless detonators demonstrated the feasibility of carrying out blasts with preloaded panels, without restrictions on the number of panels or detonators, enabling vibration control, innovating mine planning and increasing safety and productivity

Jan 1, 2024

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

By James R. Houston, Wendel Clay Chaffin, John Loviza

During the spring and summer of 1993 the largest pipeline in Tennessee was installed as part of the upgrading of Nashville's sewage needs through the year 2035. This new 3.3 million dollar outfall project is able to carry 330 million gallons of treated sewage water daily. Special projects required special equipment as this project was safely and quickly installed.

Jan 1, 1995

By John L. Floyd

One of the key factors that controls the overall profitability of surface operations is the required volume of excavated material. If the overall angle of final walls can be maximized the amount of material excavated will be reduced. However, as the slope angle becomes steeper the wall's factor of safety decreases. As a result, the development and implementation of efficient wall control blast designs becomes critical to achieving stable walls. Many site specific conditions should be taken into account when defining the methods that will be used to lessen blast induced wall damage. This paper will discuss the steps needed to properly evaluate the site and develop efficient designs. Four variations of wall control blast designs will be evaluated in terms of cost and performance. In addition, the paper will include the quality controls needed to successfully implement and refine the blast design.

Jan 1, 1998

By Thierry Bernard

New technology to automatically design a blast based on autonomous drone. The process of flying a drone, calculating the 3D cloud of points, generating the critical face profiles and placing holes automatically according to burden specification becomes fully automatic. A nice time saving with more efficiency

Feb 1, 2020

By Eric Reale

The New York City Department of Environmental Protection (DEP) is currently building City Water Tunnel #3 beneath the city. The purpose of this tunnel is to improve water distribution to the city and to allow the DEP to inspect the older tunnels and make the necessary repairs. These older tunnels have been in continuous operation since the early 1900's. Construction on the Third Tunnel is planned in four stages. The Nelson Street Shaft, which is the focus of this paper, is part of the second stage.

Jan 1, 1989

By Alton Dunaway, Kevin Sullivan, Charles Gray, Doug Hall, Kevin Grant, Kelly Thiel, John Paulson, Bruce Leland, Cole Boyd

Beaver (Castor canadensis) are responsible for economic losses exceeding $4 billion over the last 4 decades in the southeastern United States alone. A large portion of these damages occurs to public roads and highways, forests, agricultural resources, and other property from flooding caused by beaver dams. The United States Department of agriculture, Animal Plant Health Inspection Service, Wildlife Services (WS) program is a non-regulatory Federal program directed by Congress to assist resource owners with managing damage caused by wildlife.

Jan 1, 2007

By Minoru Kawamora, Koichi Kurokawa, Kenji Hashimoto

We developed concentrated remote control blasting system to blasting simultaneously at a large number of sites in a mine of large scale. This system is consisted of three parts, the first part is a control station with high voltage power source units, the second part is a relay terminal with relaying and branching units, and the third part is a blasting machine with charging and discharging units. The control station is connected with the blasting machine by mean of control bus wire. The blasting machine adopts MBS(electromagnetic induction blasting system) for the reason of safety and good handling.

Jan 1, 1990

By A. W. (Sandy) Neilson

Whether you are a general contractor who hires subcontractors to perform blasting work or you have your own blasting crew, it is extremely important to understand how Business Liability Insurance works, regardless of who is ultimately providing the coverage. If close attention is not paid to the limitations and preblast survey requirements under most policies that provide blasting coverage, you could find yourself facing an uninsured loss.

Jan 1, 2002

By Alejandro Berrios, Matheus DaSilva, Erick Siqueira

Vazante mine is an underground polymetallic mine that produces zinc, lead, and silver, which belongs to Nexa Resources in Minas Gerais, Brazil. The mine, a sublevel stope underground mine, mainly applies two subvariants: VRM – Vertical Retreat Mining and Open Stope. In a specific place of the mine, the geology allowed the design of a production stope with larger dimensions than the standard stopes, commonly called Super Stope. At this place, the plan was to apply both sublevel variants simultaneously. This mining block comprises rings in two different levels, with access by two ore drives on each level; the dimensions would be approximately 50 meters high, 50 meters long, and 35 meters wide. Opening the Free Face to mine the whole Stope was a challenge due to operational issues, such as hazard risks from loading over void space, exposure to uncontained places, and the impossibility of implementing the optimal blast sequence. Wireless blasting initiators have gained popularity recently due to their convenience, safety, and efficiency. This initiation system was applied to preload all the rings required to open the Free Face, ensuring a safe and optimal blast sequence. Wireless initiation prevented hazard risks, enhanced the blast sequence to guarantee the required void space, and optimized the equipment's operational cycle. The blast crew carried out the activity without exposure to the risk of loading over void space. The wireless detonators also avoided after-blast activities, which were required to provide secure access to the blast crew, optimizing the operational cycle.

Jan 21, 2025

By Joe Dannenberg

A word of preface: The material contained in this talk is not completely original. Many thoughts and actual words come from a fine little book called "1,000 Years of Explosives" by William S. Dutton. The book is now out of print, but if there is enough interest shown by this Society, perhaps we can have it reprinted.

Jan 1, 1980

By Thomas E. Lobb, Harry C. Verakis

Blasting is a primary means of extracting minerals and ores at surface mining operations. The domestic consumption of explosives and blasting agents during the year 2001 was about 5.25 billion pounds. Flyrock is always a major concern for the blaster. Flyrock from surface blasting operations has caused serious injury and death to employees and other persons. Injuries due to flyrock and the lack of blast area security accounted for over two-thirds of all blasting-related injuries in surface coal, metal, and nonmetal mines during the period 1978-2002. Selected accidents due to flyrock and lack of blast area security in surface mining are presented in this paper. Incidents related to construction blasting are also described. Techniques to mitigate blasting accidents are discussed. These include proper blast design, driller-blaster communication, inspection prior to loading and firing the blast, removing employees from the blast area, controlling access to the blast area, and using a blasting shelter. An experienced driller could detect potential problem areas such as voids, mud seams, incompetent rocks, and other irregularities by observing the progress of drilling. The drill log should include the details of any unusual or exceptional circumstances noticed during drilling. A blaster may need to alter the loading configuration to alleviate potential problems. Basic blast design is sometimes taken for granted and assumed to be proper for the conditions encountered, but one size does not fit all. It is known from the physics of blasting that the explosive energy takes the path of least resistance. The path of least resistance could generate flyrock, depending on the blast site conditions. A combination of ‘borehole tracking’ and ‘laser profiling’ can assist in improving the design of a blast. The blaster can use these tools to adjust borehole loading to match site conditions.

Jan 1, 2004

By Jared Redyke

Thursday, October 14, 1999 marked another important milestone for America’s space program. At exactly 10:05 AM EST on a beautiful, sunny Florida morning, Dykon, Inc. of Tulsa, Oklahoma detonated approximately 300 pounds of explosives to fell the seven million pound Umbilical and Mobile Service Towers at Space Launch Complex 41 (SLC-41) at NASA’s Cape Canaveral Space Station. Completed in 1965 at the height of the Space Race to the moon, the Mobile Service Tower/Umbilical Towers (MST/UT) were part of the Titan rocket launch facilities. The MST was 265 feet high and weighed over five million pounds. The UT was 175 feet high and weighed over 2 million pounds.

Jan 1, 2001

By Ravi Sahu, Kris Jeremiah

This paper aims to study the benefits of using Post Processed Kinematics(PPK) surveying methodology combined with Drone photogrammetry to achieve highly precise positioning (X, Y, Z) of drill holes based on the drill pattern and to highlight innovative workflow of transmitting the drill plan to smart drills for accurate drilling.

Feb 1, 2020

By Alastair Torrance, Gary Cavanough

Over the past two years a research project has been performed on reactive and hot ground. A key finding is that host materials including carbonates and coal are inhibitors to the reaction of sulphide and nitrates. The mechanism of this inhibition is pH buffering and isolating the surface of sulphide from reactants. It has been identified that acidity is a key driver of the reaction with a pH of 2 required for a reactivity event. A series of decomposition experiments confirmed that reactive and hot ground are essentially the same phenomenon with the heating produced either by the reaction of sulphide with nitrates or an external heat source. The results indicate that the key driver of detonation in reactive ground is energy and heat released from the acid induced reaction of sulphide and nitrate with no indications of sulphide being a catalyst or contributor to detonation apart from being a heat source. There must be sufficient sulphide and thermal insulation to provide and retain enough heat for detonation to occur. A pathway to detonation is postulated whereby the heat travels upwards and results in evaporation of water in the explosive. When the temperature reaches approximately 200°C (400°F) the ammonium nitrate starts to decompose, decreasing the mass of the reacting species. The material in the top layers has reduced density and specific heat hence the temperature of the top region rapidly increases up to >1000°C (1800°F) and may initiate detonation. Field tests on loaded blast holes support this proposed mechanism. Case studies are presented whereby the research findings are used to provide an analysis of historical reactive ground events.

Jan 21, 2025

By Yonghun Jong, Chungin Lee

The main purpose of this study was to apply the artificial neural network (ANN) models to determine optimal powder factors and predict peak particle velocities, based on a series of observations and input parameters. The used blasthole pattern was V-cut. The locations of blastholes and ignition patterns remained almost constant. The input parameters were 14 geological conditions (i.e., dip, dip direction, spacing, separation, and persistence of 2 discontinuity sets, tunnel orientation, rock strength, RQD, and RMR) and 4 blasting conditions (i.e., distance between blasting points and measuring points, charge weight per delay, drilling length, and blasting efficiency). Data for the ANN application in this study were recently collected in a highway tunnel under construction in Korea. The main rock type in the site was biotitic granite. An optimum ANN model was determined by training models with collected data. The trained model was used to evaluate the prediction capability of the optimum model. It was shown that the ANN model could predict the powder factor and the peak particle velocity depended upon the selected input parameters. Particularly, the ANN model predicted more accurate peak particle velocities than those obtained by the blasting vibration equation. Moreover, the more dominant factors among the input parameters could be determined by analysis of the relative strength effect.

Jan 1, 2002

By Clara Godoy, Álvaro Dapía, Paulo Couceiro, Håkan Schunnesson, Juan Navarro

This paper applies geostatistical tools in Measure While Drilling (MWD)data to estimate the probability distribution of values in all the points of the studied domain in order to assess the continuity of rock classes between boreholes. The analyses carried out by Ghosh et al.(2018) and Navarro et al.(2019) have been used as starting point of this work to classify the geotechnical rock condition in four classes: solid rock, fractured rock, cave-in rock and cavity. From it, an application for the geotechnical rock condition of ore bodies have been developed, aiming at characterizing the rock before the charging the holes to minimize unexpected rock conditions and to address issues associated with charging and blasting operations. Such problems are closely related with non-optimal rock fragmentation after blasting. The procedure has been applied in the geotechnical block model results obtained from Navarro et al.(2019)’s work in the Luossavaara-Kiirunavaara AB’s (LKAB) Malmberget underground iron ore mine, Sweden. Navarro et al.(2019)’s model was developed based on102 fan-holes from five ore bodies and extrapolated to the full-scale in20 drifts with 5600 fan-holes from two orebodies. A multi-step transformation of the MWD parameters was carried out in order to minimize external influences other than the rock mass. The study shows the calculations of the variogram and kriging estimation in the 3D domain for six ring-blasts, from one of the ore bodies studied in Navarro et al. (2019)’s work to assess the continuity of the rock classes along the six ring-blasts in a 3D mapping model. For that, intermediate rings between the measured ones from the MWD have been estimated. The probability distribution of values in the entire domain of rings with measured samples has been plotted together with the rock classes identified by the blasthole paths. The results show high accuracy in the matching between the kriging and the values given by the MWD data, allowing to visualize smooth trends of different rock classes along the ring. The representation of the 3D mapping model for the six ring-blast shows clear fractured and cave-in zones developed along the drift that correspond to zones with geotechnical problems found, as from internal reports.

By Gary B. Hemphill

Each year the demand for precision blasting increases due to the reduction in the amount of prime land. More site preparation and hone building requires blasting than they did a decade ago, Because of this increased need for blasting in more populated areas, the need for blasters and engineers knowledgeable in work involving blasting nets has increased.

Jan 1, 1978

The quiet banks of the Maumee River in Toledo, Ohio, received a wake-up call July 16 as two smokestacks in the Marina District were leveled with dynamite. B&B Wrecking, Inc. of Cleveland contracted the project with the city to bring down the twin stacks, both measuring over 250 feet tall. The structures were part of the Toledo Edison Steam Plant and were erected nearly a hundred years ago. A week’s worth of preparation went into final planning, drilling and loading holes with over 80 pounds of explosives. The felling went precisely as planned as onlookers cheered as the stacks were reduced to rubble.

Jan 1, 2015

By Edward J. Jr Walter, Edward J. Walter

The vibration problem is approximately fifty years old. The original investigation of the U.S. Bureau of Mines was begun in 1930. Significant investigation into the problem was done by Crandell, Langefors, et al, Edwards and Northwood, and again by the Bureau of Mines. This resulted in an effective Safe Limit standard expressed in particle velocity as 2.0 inches per second.

Jan 1, 1979