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By Jorge Cárdenas, Diego Gamarra

In previous phases of the mine, a landslide resulted in several losses in production delays. The stability of slopes in a mining operation is critical for the sustainability of the operation, as they are exposed to vibrations and damage caused by blasting. Therefore, it is essential to implement controls and innovative technologies to reduce these vibrations levels. This study focuses on the application of low-energy emulsions with lower densities than conventional explosives, developed to reduce vibrations and the energy delivered to the rock mass adjacent to the near blast holes as a buffer row. Near field studies were carried out by embedding triaxial geophones. Vibrations were recorded, and mathematical models of vibration associated with different types of explosive mixtures were generated. This allowed us to determine the benefit of implementing low-density explosives in reducing vibrations compared to Heavy ANFO explosives. The application of low-energy explosives with densities ranging from 0.7 to 0.8 g/cm³ and Relative Bulk Strength (RBS) of 51-65 allows for a 40% reduction in vibrations compared to the detonation of Heavy ANFO explosives.

Jan 21, 2025

By Calvin Konya, Steven S. Spagna, Ed Smith

During Summer 2001, the U.S Army Corps of Engineers awarded a contract to the construction firm of Bush and Burchett of Allen, Kentucky, for the purpose of developing a 13 acre redevelopment site by removing approximately 2.5 million cubic yards of rock (fig. 1). The Redevelopment Site will be the future home for a large portion of the City of Grundy, Virginia. Additional work items include the construction and relocation of 3,000 feet of the Norfolk Southern railroad bed, the placement of 95,000 cubic yards of fill and the placement of 16,000 cubic yards of stone slope protection along the Levisa Fork River. Bush and Burchett received a notice to proceed with construction in July 2001. Currently, the contract is near completion. Current activities include: hauling of material from the Redevelopment Site to the disposal area; placing fill material on the Redevelopment Site, and placing Stone Slope Protection (SSP) along the Levisa Fork river. Approximately one year into the construction highly weathered rock, degraded to near soil- like condition, was encountered in the upstream portion of the excavation. Over one-third of the original cut slope was adjusted and the blasting specifications had to be amended to accommodate for the material that was encountered in this area.

Jan 1, 2005

By L. Wilson, M. Kotzel, T. Pienaar

An empirical equation is presented for the maximum airblast from unconfined charges. This has been tested at a number of sites and with charges ranging from 0.1kg to 311kg. The equation is developed to predict community response to potential explosive test range sites and the testing has added to our knowledge of the effectiveness of mitigating measures. The first site had 10m to 15m high walls that were intended to ameliorate the airblast. These walls functioned to a limited extent and reduced the airblast levels by 2dB to 5dB. The airblast was affected somewhat by topography. Noise levels at the nearest residences exceeded 130dB for charges larger than 1kg, whereas the vibration levels were very small. Formal complaints were received where the airblast level exceeded 128dB as per conventional expectations. Pedestrians and pets in the suburbs were startled by the blasts, emphasizing that the community response is much more sensitive to noise and airblast than vibration levels. The maximum airblast levels were too high for this site to be used on a regular basis. At another site, the airblast levels were significantly increased downwind by up to 10dB due to a moderate wind. A third site, at a quarry, produced unconfined airblast levels beneath the derived limits, but are much higher than the normal quarry blasting. By involving community forums there were no complaints, possibly due to desensitization by the normal blasting activities. The study has highlighted new areas for research in understanding the effect of noise, air blast and vibration on the low cost and informal housing typical in South Africa

Jan 1, 2011

By Behrouz Ohadi, Kamran Esmaeili, Bibhu Mohanty

In most metalliferrous open pit mines with heterogeneous orebodies, blast-induced rock movement is a crucial outcome that has unfavorable impact on ore and waste segregation in the post-blast muck pile, resulting in either ore loss (the ore is misclassified as waste and sent to the waste rock dump) and/or ore dilution (waste is misclassified as ore and sent to the processing plant). While many studies have been carried out to assess the influence of blast design parameters on blast-induced rock movement, the influence of rock mass characteristics in these studies have been overlooked.

Jan 1, 2018

By Ken Schei, Martin Reed, Samuel Bowser, John Wright

From October 18 through October 21, 2001, United States Antarctic Program blasters opened ten access holes for research divers in 11-ft. thick sea ice at Explorers Cove, McMurdo Sound, Antarctica. During this project, a blasting seismograph with a hydrophone accessory was used to monitor the underwater shock waves associated with the blasting technique. Shock wave values averaged 42.3 psi for initial (cratering) shots and 5.9 for subsequent clearing shots, indicating that the ice absorbs most of the shock wave. The results also provide data for refining safety protocols for divers and for the protection of marine biota.

Jan 1, 2003

By Miguel Humpire Huamani, Gustavo Huerta Valer, Jorge C. Cárdenas Miranda

As part of the continuous improvement and increase productivity to achieve the mining and extraction plan of a low-grade open pit copper operation, alternatives are required to expand the blast pattern to maximize drills and steels resources along to ensure the fragmentation results for the process plant with volumes from 500k tons of broken material per day. Therefore, the application of aluminum based ultra-high energy explosives was an alternative to achieve the objective of expanding the production pattern by 34% while maintaining energy factors levels along with the distribution of explosive and the application of the pocket charge in the stemming level, reducing the load factor, maintaining the fragmentation results in P80 and increasing the percentage of fines less than 1.0 in (2.54 cm). An important development to ensure the supply and perform successfully blasthole loading was the implementation of a supply system with pre-blending (aluminized emulsion) which is stored in silos and load through factory trucks. In the field we ensured optimal initial and final density levels with chemical sensitizer to perform the most fracturing work in the rock, complementary evaluations were performed to predict flyrock and define safe equipment evacuation radiuses along with advanced vibration monitoring for the sustainability of the mine.

Feb 6, 2023

By Christopher Jon Preston, Troy Williams, Daniel Roy

There has been significant progress made with narrow vein gold mines in which a second option for crushing has begun to attract attention. To ensure the profitability of a mine that has based its economics on the absence of a crusher station, more than just best blasting practices are required. Using a blasting operation itself as a primary crusher would undoubtedly save enormous capital costs as well as eliminate some of the costs of crushing ore with the result that considerable savings might be realized. The challenge would be to define the conditions necessary to make this type of operation feasible by providing consistent blasting methods that result in a significant paradigm shift with respect to both blasting and current underground crushing methods. A break model has been developed and applied as a technique in designing blasting patterns based on a unit charge blasting geometry and stress reflection from free faces. There are four components to this model and these are 1) unit charge, 2) thermodynamic/energy, 3) stress reflection, and 4) radial break. Some important changes in timing between holes and rows based on rock properties and the percentage of burden moved were also used. On-site testing at a narrow vein gold mine in Quebec Canada, provided measured parameters for the model. No underground crusher was planned - relying only on the fragmentation profile generated by ring blasting. The specification for muck was that the fragmentation profile needed to be 100% < 400 mm (16 in) with no overbreak - with dilution less

Jan 1, 2019

By Thomas Kovalchuk, Kenneth Eltschlager, William Shuss

In April of 2000, two adults and their newborn infant, were poisoned by carbon monoxide in their home and received medical treatment at a Pennsylvania hospital. Carboxyhemoglobin levels were; child - 3 1%, father - 28Oh, and mother - 17%. Initially the furnace was blamed but after further review, blasting at a nearby coal mine was determined to be the source. All other sources of carbon monoxide were ruled out. The blasting was about 400 feet from the house. The conditions that led to the migration of gas include: the blasts were highly confined, the geologic structure contained fractures that served as conduits for the carbon monoxide to reach a hand-dug well outside the house, and the well was atmospherically connected to the basement floor drains.

Jan 1, 2001

By Scott Scovira

All flyrock incidents have the potential to result in injuries or fatalities that can result in loss of company reputation, license to operate with clients, and bear the exposure to high cost liability. From 2007 to 2009, one NA Quarry and Construction Business experienced a series of flyrock incidents. In the Spring of 2009, this business declared that the frequency and severity of Flyrock Incidents had reached an unacceptable level. A Flyrock Elimination Program was launched.

Jan 1, 2012

By Tapan Goswami

A column of stemming material keeps explosion gases at high pressure for longer times in a blasthole. In general, use of appropriate stemming enables the achievement of the desired level of fragmentation and looseness of muckpiles, as well as the reduction of airblast and fly rock. The ejection resistance of a stemming column varies with the type of stemming material employed. In an effort to optimise stemming at Mt Owen Mine in the Hunter Valley, Australia, a trial was conducted to assess the efficiency of two types of stemming materials. Mt Owen mine relies on through seam blasting and stemming quality is important in this challenging blasting environment. Each type of stemming was trialed in different section of a blast. The blast was designed using Orica’s SurveyPlus@, LoadPlus@ and ShotPlus@ software. Measurement was done using high speed filming of the blast and then post blast information was obtained from analysis of the film. Data analysis included determination of the ejection velocities and percentage swell. Digging rates were measured from excavator production rates. Despite the presence of rounded surfaces and finer particle sizes, River Pebble stemming material showed superior ejection resistance. It also appeared to perform as well as more angular and expensive Crushed Stone, a finished quarry product, based on excavator productivity and heave. It was recommended that future blasts at the mine be stemmed with the River Pebble stemming material.

Jan 1, 2000

By Perry Sisk

In order to protect nearby structures during a blasting project, a peak particle velocity limit is often stipulated by a government agency or the owner of a particular structure. At the start of a blasting project, a preliminary estimate for the minimum scaled distance is often determined using a vibration prediction equation before any site-specific data have been obtained. Reasonably conservative assumptions are typically made for the unknown input variables in the vibration prediction equation until site-specific blasting data have been obtained and evaluated. Although this approach is prudent, it provides no assurance that the peak particle velocity values generated during the initial phase of the project will be below the specified limit.

Jan 1, 2013

By Rolf R. Schillinger

It is established to an increased extent that the basic questions about raw material extractions deal with water, dust, noise and vibrations. If it has not been definitely proven that these points won?t lead to excessive environmental strains, attempts at any explanations will meet with disapproval in advance. In order to answer the basic questions about dust, noise and vibrations quality management becomes most important, particularly with respect partly unavoidable emissions of production processes. The specific questions have to be answered within the context of good blasting practices, latest discoveries of the explosives industry, and by use of a Blasting Works Quality- Management, which includes both production quality and Risk-Management. The paper shows a practical way to work out a Quality-Management Program for companies involved in blasting activities.

Jan 1, 2002

By Dominic C, Gregory B. Poole

On December 12, 2018 at 4:14 AM EST, an earthquake registering a 4.4 magnitude on the Richter Scale occurred in central Tennessee. According to a survey posted on the USGS website, this earthquake was felt throughout the southeast and even as far away as Arnold Nebraska. That’s over 900 miles (1,448 kilometers) from the epicenter. We recorded the vibrations from this earthquake on 44 different seismographs that were set up with remote access to continuously monitor vibrations from blasting activities. Having this data gave us an opportunity to compare the vibrations caused by earthquakes and blasting. A simple observation of the amplitudes, frequencies, and durations is enough to notice that vibrations from earthquakes are very different than vibrations caused by blasting in mining and construction

Feb 1, 2020

By Kain Petterson, P D. Katsabanis

Blast fragmentation, determined using image analysis was correlated to drill monitoring parameters in an open pit operation. Average fragment size and 80% passing size showed strong correlation with specific energy of drilling as well as with torque, while the same passing sizes did not correlate well with the rate of penetration. It was also determined that the uniformity of fragmentation decreases with the specific energy of drilling. Thus drilling monitoring parameters appear to be valuable in determining the blastability of the rock mass, enabling adjustment of blast loading to respond to changing conditions in the rock mass.

Jan 1, 2013

By Vitor Barcelos, Eduardo Elói, Gabriella Vaz, Davi Oliveira, Leandro Silveira

Following a routine production blast at Vale S.A.'s Itabira Mine in the Quadrilátero Ferrífero region of Minas Gerais, Brazil, nearby residents registered complaints about blast-induced vibrations. Analysis of the blast footage revealed that multiple blastholes were detonated simultaneously, resulting in a higher-than-expected charge per delay, ground vibration and cratering even though the electronic delay timing was configured correctly. Subsequent blasts within the mine's soft schist region confirmed the occurrence of sympathetic detonation. Mitigating or eliminating this phenomenon is critical for the mine's operation. Two dynamic pressure tests were conducted using carbon resistors together with typical VOD monitor maintaining the standard booster, electronic detonator, and a blend of 70% emulsion with 30% ammonium nitrate explosive. The tests involved increasing the distance between the central hole (detonated first) and the four surrounding holes in a five-hole sequence. Unfortunately, sympathetic detonation occurred in all these tests. To address this issue, a new explosive with a lower density and detonation velocity was tested. This approach proved promising, as no sympathetic detonation occurred. By leveraging the data obtained from this study, engineers can now identify situations at risk of sympathetic detonation and implement preventive measures, such as selecting the appropriate explosive and recommending safe minimum burden and spacing settings as well as confinement level for each blast while maintaining the desired level of rock fragmentation.

Jan 21, 2025

By Frederick B. Kuhnow

Harmonic energetic delamination of T2 building is being considered for demolition at a formerly known atomic lab. The T2 building is within a containment structure that is under a negative pressure of -49 Pa (-0.2 inches of WC) so that no remaining radioactive material is leaked out. The T2 containment enclosure is a portal frame-type system that spans east/west over 35.05 m (114’-11 7/8”) and spaced 2.9 m (9’-6”) apart. The west side of the portal frames is supported by a 64 cm (2’-1”)thick concrete wall which is backfilled to the west and open to the T2 basement to the east. The east side of the portal frames is supported by a 61 cm (2’-0”) thick concrete wall that is backfilled to the east and open to the tank farm vaults to the west. A concrete slab-type footing supports both the east and west walls. Transverse walls provide lateral support for the walls as part of the original design. The west wall has an elevated slab that provides further stiffening of the concrete wall between the transverse walls.

Jan 1, 2017

By Diogo Fonseca, José Manuel, Nuno Fernandes, Francisco Monteiro, Andrew Palangio, Blessing Taiwo

This study aims to enhance the integration between blasting and primary crushing operations in quarrying by optimizing the size of oversize and bypass fragments, ultimately reducing energy consumption. Using simulations of multiple blast rounds at the dstgroup aggregate quarry in Portugal, the research seeks to refine blasting practices and improve crushing efficiency. Part 1 of this study, presented at the International Society of Explosives Engineers' 51st Annual Conference, introduced a baseline framework for assessing the compatibility between blasting outcomes and crusher requirements. This methodology was applied to two blasting rounds, revealing discrepancies between expected and actual fragmentation results. The assessment raised key questions, including the root causes of fragmentation mismatches and the identification of controllable parameters that can be adjusted to align the particle size distribution (PSD) with the crusher’s optimal input range. Based on these findings, six key modifications were proposed to improve blast performance: (1) reducing the drill and blast pattern to limit boulder formation in the overlapping regions of hole influence, (2) increasing both the size and length of stemming material to enhance energy confinement, (3) decreasing subdrill depth to prevent toe burden issues from toe deviation, (4) modifying inter-hole timing to relieve back hole burden, and (5) improving drilling accuracy. Part 2, presented at Fragblast 14, explored advanced modifications to the initial blast design. The first adjustment was reducing subdrill and altering stemming material resulted in an 11% reduction in D80, a 19% decrease in maximum fragment size, and a 21% improvement in blast fragmentation efficiency. These changes shifted the PSD by 15% closer to the crusher compatibility envelope established in Part 1. Despite these improvements, boulder generation persisted in the front and back rows of the blast. This third part of the study focuses on implementing the remaining recommended modifications from Part 1 to further enhance blast efficiency and ensure crusher compatibility. The findings contribute valuable insights into the benefits of integrating blasting and crushing optimization strategies to achieve more consistent and efficient fragmentation outcomes.

Jan 26, 2026

By S B. Richardson, D Mead, N T. Moxon

The use of air-decks to reduce explosive costs has become very topical in recent years. The majority of the research in this area has been arried out between the Soviet Union where reductions in explosive consumption of between 10-30% have been claimed with apparent benefits being gained in both fragmentation and movement. Work carried out by the University of Maryland using thick plexiglass blocks has supported these findings and indicated that air-decks in measetbe duration of action of the shock wave on the surrounding material by a factor of 2 to 5 (see Figure 1). Although the fracture network resulting from this mechanism is not as intense as that produced adjacent to the explosive charge it does appear to act over a larger volume of material. Although the mechanism attributed to air-decking has been studied in some detail the effect of this mechanism on the size distribution of material produced during a blast does not appear tot have attracted much attention.

Jan 1, 1991

By César Ugaz, Jorge Cardenas

Mitigating the vibrations resulting from a blasting rocks is one of the most common challenges that Peruvian mining has, since if this impact is not mitigated it can generate discomfort and altercations with neighboring communities and also puts the continuity of the mining project at risk. In that sense, we must establish control parameters to mitigate these effects as much as possible. As a starting point we must establish areas of interest that in this context would be the communities near the mine; first stage to carry out constant monitoring at these points, the registration of vibrations and noise is vital for the success of this control, with this information we can establish predictive models, the registration of elemental waves and the evaluation of human perception. In a second stage, this information allows us to make decisions in engineering such as the selection of delay times, elaboration of detonation sequence schemes, maximum amount of operating load per delay window, as well as the use of special load designs (Decks). There is a fear that these controls generate negative impacts to the process, referring to fragmentation, dig rate, throughput, etc. Since we limit the explosive load necessary for the results we need. To avoid this we use "Decks" type load designs under a sequencing between these under time calculations by elemental waves, which generate a reduction in vibrations up to 50%, also complying with strict regulations without affecting the power factors to comply with our performance indicators. Finally, in a third stage we must carry out a constant evaluation of results according to the progress of the mine.

Jan 26, 2026

By Tyler Rockley, Cara Rosen

Blasting at a granite quarry in eastern Maryland produces elevated air blast readings that can fall into the cautionary zone for the state of Maryland environmental regulations on a semi-regular basis. When designing blast patterns in this quarry, challenging geology creates rough and uneven blast faces that can be difficult to capture with 2D laser profiling fully. Utilizing several methods known to manage high air blast results like pattern adjustments, decking, and timing changes have not achieved consistent outcomes.

Feb 1, 2020