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By Richard Turnbull, James Purssey

"The Northconnex Project is a twin nine kilometre tunnel in Sydney, Australia, linking the M1 PacificMotorway at Wahroonga to the Hills M2 Motorway at West Pennant Hills. Access to the tunnels will befrom portals at either end and from three vertical shafts spaced along the length of the motorway. These shafts will provide access for equipment, plant and personnel, removal of spoil during construction,ventilation, and emergency egress points during tunnel operation. The three shafts have a 12 m x 16 m (39 ft – 53 ft) cross sectional area and depths ranging from 45 m to 91 m (148 ft – 299 ft). The vibration limit for the shaft blasting was set at 10 mm/s ppv, with residential properties as close as 31 m (102 ft) and the existing M1 motorway 80 m (262 ft) away. The traffic volume for the M1 is 80,000 vehicles per day and Northconnex will provide an additional 100,000 vehicle capacity. "

Jan 1, 2017

By Ye Yuan, Jaak Daemen, Shaguo Yuan

ABSTRACT: A 400m2 (480 yd2) heavily reinforced high-strength concrete slab 800mm (31 inch) thick had to be demolished. Underneath it was a 300mm (12 inch) thick underlying structure consisting of three layers: a cushion coat, a water barrier and a concrete layer that protected the water barrier. It was strongly desired by the owner that the underlying structure, especially the water barrier, remain undamaged during the blasting demolition of the reinforced concrete slab above it. This paper discusses the design of the demolition blast, problems encountered, and practical solutions to these problems. First, the impact caused by the charge explosion on the remaining structure was studied. In order to limit crack propagation in the concrete to the bottom of the concrete layer, the concrete isolation layer underneath the bottom of the slab to be demolished was left in place, to protect the water barrier and its protection layer. The effects of blasting vibrations on adjacent concrete were analyzed and precautions were proposed in the design. A safe blast design meeting the requirements to protect the water barrier below the slab was detailed. Rainwater collected and stored above the remaining underlying structure remained in place for two weeks, confirming that the design and blasting were successful.

Jan 1, 2010

By E. Contestabile, B. von Rosen, P. Lightfoot

As part of an accident investigation ANFO was subjected to various abusive tests. A tractor-trailer carrying 18,000 kg of blasting explosives, caught fire, burned for approximately 30 minutes, and then detonated. A series of tests was designed to observe the behaviour of ANFO when subjected to different thermal stimulus tests and more specifically, the Height-to-Detonation Test. Three diameters of steel pipes were used in the Height-to-Detonation Tests thereby simulating cylindrical columns within a pile of ANFO. The ANFO samples were then subjected to various thermal stimuli to initiate a reaction. Through the use of some instrumentation, the response of large ANFO samples was recorded and its behaviour, including the occurrence of phase changes will be analysed.

Jan 1, 2001

By Tyler Rockley, J. P. Remi Proulx, Ruilin Yang

A highwall blast vibration project was carried out to quantify the level of blast vibrations produced from a trim blast in soft rock and a combined production and trim blast in hard rock. Combining production and trim blasts could be performed without exceeding the mine’s vibration limits.

Feb 1, 2020

By Tristan Worsey, Nathan Rouse, Evan Thibaud

Electronic detonators allow for variability and accuracy with blast delay selection and timing sequence. However, a single published guideline for selection of electronic timing delays is not available on the OneMine database. There are published documents that present options for timing with electronic detonators, some of which provide great detail and scientific evidence, but there is no single document that presents several different approaches with simple instructions on how to apply the various timing approaches. This paper reviews published electronic timing approaches and results, then presents guidelines for electronic timing for alternative mining methods, which include: bench blasting (ie. quarries) and crater blasting (ie. metals mines). Most of the approaches are based on calculating milliseconds per meter for rock types, as quantified by the rock sonic velocity. Guideline calculations are provided for recommended hole-to-hole delays and row-to-row delays for both free-faced bench blasting and crater blasting approaches. These are the two most common blasting methods for mining operations. Typically, free-faced bench blasting is the approach used in quarries with a bench height to burden ratio of around 4, and crater blasting is typically used in large blasthole diameter/short bench blasting in metals mines with a bench height to burden ratio of around 1. Mines may focus on fragmentation, mucking rates, ore movement distance and movement direction. Recommendations are also included to provide general recommendations based on a mine’s preference for movement and fragmentation. References include twelve studies on bench blasting and six studies on crater blasting. In addition, a discussion is included on the application of these recommendations at a full-scale surface gold mine.

Jan 21, 2025

By Stephen G. Rieben

Almost everyone has at least heard of the two one-call systems which serve New England. They are "Call Before You Dig", which covers Connecticut, and "Dig Safe", which covers the remaining five New England states. Those of you who are more familiar with these programs know that it is our job to help guard against the accidental dig-ups of buried plant and to prevent facility service disruptions. We cover all types of buried facilities, from cable television to high pressure gas transmissions lines, telephone cables, electric facilities, fiber optics and everything in between

Jan 1, 1990

By Dale Ramsey

As someone who has enjoyed photography as a hobby for many years, aerial photography to me has always been an exciting way to give a different perspective to my images. Our industry is always in search of new technology for bet­ter and more cost effective methods to improve our trade and aerial photography is a great tool to improve project planning or document its progress. It has typically involved conventional aircraft both fixed wing and helicopters but neither method is always available or cost effective. The lat­est innovation since digital imaging is the development of Unmanned Aerial Vehicles (UAVs) or drones. But there is a lot of uncertainty with this amazing new technology’s fu­ture in the U.S. as the Federal Aviation Administration (FAA) is under review and development of UAV regulations for commercial use which are slated to be completed in 2015.

Jan 1, 2015

By Michael Burrell

This project involved the protection of an historic landfill located on the site. Construction blasting was for a permanent access road to carry traffic to and from a new metal processing plant being constructed nearby. The landfill contained materials disposed of during the closure of a Phosphorus plant that had previously occupied a portion of this site.

Jan 1, 2012

By Brent Blanchard

As most veterans of our industry are aware, explosive demolition by its very nature is often a challenging proposition. Even under the best of circumstances, proper planning and care must be taken during a variety of processes to ensure a safe, successful result. However, every now and then a project suddenly arises where safety, timing and cost factors combine to form a critical scenario requiring rapid execution in an environment far more challenging than the norm. On these occasions, the stresses, complications - and most notably the dangers - related to the industry increase exponentially, and conspire to test the mettle of even the most seasoned experts.

Jan 1, 2003

By Aris Tambunan, Nella Lubis, Nurafrianti Saala, Komang Widhiayanto, Herry Saputra, Rudolf Sitorus

Maximizing mining recovery rates and minimizing ore loss are pivotal objectives for economic efficiency and operational effectiveness. This study explores methods to address these imperatives by enhancing ore production and recovery through improved blasting techniques and spillage control in the Martabe Gold Mine Project in North Sumatra Province, Indonesia. Between 2018 and 2021, the average mining recovery rate stood at 93%, resulting in a potential annual ore loss of 7% and a potential quarterly financial impact of close to $2 million. Maintaining and enhancing mining recovery became crucial, with a planned 30% increase in total material movement for 2022. The mining recovery target for 2022 was set at 96% based on best achievement historical data from 2021 to increase ore tonnage by 203 KTon per annum. To achieve the primary objective of increasing ore production by improving mining recovery, the study focused on predicting and controlling the movement of blasted ore to reduce spillage and enhancing the grade control model to reflect actual conditions post-blasting. Several alternative solutions were explored, primarily emphasizing drilling and blasting activities. Essential methods included capturing the actual blasting movement to adjust the ore block based on blasting design data and post-blasting muckpile topography. This approach minimizes ore loss by providing output as ore block adjustment based on post-blast movement data. In addition, the tie-up design was adjusted to control ore spillage outside the pit ridge. The implementation of these methods yielded significant improvements. Adjusting the ore block based on actual blasting movement contributed $1,545,764 in benefits. Controlling ore spillage outside the pit ridge achieved a 10% reduction in spillage, contributing $79,184 in benefits. These enhancements successfully met the 2022 mining recovery target of 96%, marking a 3% increase from 2021. Consequently, ore loss was reduced by 178 KTon throughout 2022, resulting in a financial impact of $7.3 million. The study underscores the significance of precise blasting techniques and effective spillage control in enhancing mining recovery rates.

Jan 21, 2025

By N. Rouse

Underground raises and slots are a vital part of underground blasting operations. Raises and slots are vertical shafts or openings used for ventilation, ore passes, or creating voids in stopes. In the author’s experience, raise and slot designs can vary significantly from operation to operation or even within a single operation, sometimes for reasons unknown. The results of the various designs can differ depending on drilling accuracy, geology, and the explosives used in the design. The purpose of this paper is to summarize the recommendations found in published literature on raise and slot design in one document, while incorporating some of the author’s own experience with optimizing raise and slot designs in underground operations. Some inspiration is also included from burn round designs; small versions of raises drilled horizontally in development blasting rounds. This document includes discussion points on drillhole diameter and depth, pattern design and relief requirements, explosive types and loading recommendations, and timing. Ultimately, this document can be useful to those looking to design a raise or slot blast for the first time or for those looking to improve on the results from the raise and slot blasts used at their operations.

Jan 1, 2024

By Dale Preece, Steven Case, Cassidy McAllister

Simplot Phosphates produces high quality phosphate fertilizer through open pit mining. The operation near Vernal, UT began as a three-pass mining process carried out with drill and blast followed by the combined effort of shovel-truck and dozer material removal. The first two passes removed the overburden and the final pass mined the relatively hard phosphate ore for processing at the mill. Vertical blastholes were employed in all of the mining passes.

Jan 1, 2012

By J. A. Sanchidrián, P. Segarra, S. Gómez

Blasting is a common activity in mining that can cause significant damage in the remaining rock mass. The most commonly used method for predicting vibrations is the Swedish or Holmberg-Persson approach. It is a simple and fast method that uses empirical formulation to estimate the vibration levels based on the explosive charge weight, distance to the source, and other parameters. However, it has limited accuracy and does not consider the effect of free surfaces or other boundary conditions. On the other hand, recently developed methods as the full-field solution (FFS) can provide more accurate predictions of vibrations due to excitations provoked by cylindrical columns of explosive, but the inclusion of free surfaces in analytical methods is a challenging problem. This paper presents a new approach that includes free surfaces in the FFS to predict vibrations analytically in the near-field. The main obstacle to including free surfaces in the FFS was the belief that the solution was non-decoupleable in P- and SV-waves separately. The Heelan's approach was previously used to decouple them, but it only provides valid radiation patterns in the far-field and does not account for intrinsic attenuation. In this paper, we address this problem successfully, allowing for the inclusion of free surfaces in the FFS.

Jan 1, 2024

By Peter Dare-Bryan, Will Hunt, Lee Julian

It is well-known that blasting has an economic effect on grade control activities. However, until recently, methods did not exist for measuring the grade control value change caused by the blast. Rules of thumb were the best method to minimize ore loss and dilution, as simulation has been traditionally constrained by time and computer power. Even with these rules followed, an extensive study performed on over 150 blasts showed that the value change caused by the blasts followed a normal distribution – some blasts created value, and some blasts destroyed value. The question naturally asked was “How can we ensure the blast designs are optimized to create value?” Recent advancements in computer power have enabled real-time blasting simulations that create post-blast grade control models before the blast is fired. Understanding what will happen before it happens allows blasters and grade control personnel to iterate designs, searching for the highest value achievable.

Feb 6, 2023

By Douglas Rudenko PG, Jay Elkin, Siavash Mahvelati Ph. D.

Very little studies have investigated the behavior of cracks in unlined tunnels over long periods of time, especially when such flaws are subjected to blast-induced vibrations. Using a pool of 30+ blast events, a positive correlation was found between the peak particle velocity and peak crack movement.

Feb 1, 2020

By Weiying Zeng, Shouwei Wang, Jinbei Zhong, Xiangdong Meng, Lingtian Meng

"Due to a drainage problem, the Lanzhou to Chongqing high-speed rail line had been out of service during the 2015 wet season, so a drainage tunnel is to be constructed for the line and required to be accomplished before the 2016 wet season. This drainage tunnel is only 5 meters below the line which is in service, therefore blasting vibration needs to be strictly controlled. This paper introduces all theapplied blasting methods, parameters and detonation throughout the entire project, finally bringing in the electronic detonator stagger phase technique and corresponding time difference for detonation."

Jan 1, 2017

By Greg S. Williams, David L. McDorman, Richard W. Givens

This paper examines the effect of prill size consistency, internal particle density, and oil absorbency on Ammonium Nitrate Fuel Oil (ANFO)-emulsion blends. By analyzing these physical properties of prill and the nature of the blending process, a mathematical model has been developed to theoretically predict blend densities. Calculated densities can now be compared to actual field densities to give an operator a basis for comparing various manufacturers' emulsions and Ammonium Nitrate (AN) during bid solicitation. The lowest priced emulsion and/or AN may not be the most economical, due to the impact of specific physical characteristics. These factors dictate the blending mechanics and resulting density yields for various mixes. The research was driven from observed 'field' mixing relationships and data. Ultimately, such a model can be an effective tool in evaluating blends from a cost and performance basis.

Jan 1, 1990

By Tyler Rockley, Carla Reyes

Autonomous fragmentation measurement systems designed for shovels have been in operation for nearly two decades, however fragmentation systems capable of performing in the dynamic conditions of the front-end loaders (FEL) were only recently introduced to the market. This paper presents an in-depth evaluation of an automated digital fragmentation measurement system specifically designed to perform under the dynamic operational conditions of the FEL in two of Teck’s mine sites. As early adopters of this novel application, Teck embarked on a Proof-of-Concept (PoC) trial phase, defining a set of key performance indicators (KPIs) to qualify the performance of the digital solution in tough mining operating environments. The KPIs focused primarily on the hardware robustness, quality of image and segmentation, both day and night, availability of the system and sample ratio. The benefits expected from using this technology include increasing the safety of the current fragmentation measurement process, improving the quality of the analysis, increasing the sample representativeness, and using the attributes of the system to create an oversize detection alert to inform the loading operation process. A critical part of the evaluation was verifying the system’s effectiveness on the particle segmentation algorithm as this element often gets overlooked, especially when dealing with the large number of samples autonomous systems can generate; minor misclassifications due to inadequate segmentation are often dismissed as they might not be statistically significant, however systematic misclassifications can cause unacceptable deviation in the data and limit the intended application of the technology. The system’s performance was further validated through several tests that involved identifying objects of known sizes to ensure the reliability on the consistency of the particles’ segmentation.

Jan 21, 2025

By Tom Snyder, John Brulia

Part I is the first of a series of articles by the authors on hazardous materials (HM) transportation safety and compliance for shippers and carriers who offer and transport commercial explosives in commerce on public highways in the U.S.

Jan 1, 2014

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