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By Lyall Workman

New mines are frequently located at altitudes above 3,000 meters (10,000 ft.). Drill selection must take the altitude effects into account, to insure high productivity and good bit life. In particular, compressors must be sized differently than for low altitude operation. A larger compressor is required to deliver adequate air to the bottom of the blasthole. Many drills in remote locations use diesel engines as the prime mover. Altitude effects on engine performance should also be considered.

Jan 1, 2007

By Jeffrey Meissner, Mike Waldron, Charles Dowding

Most studies of crack response have focused on opening and closing of a crack in the plane of the wall in which the crack occurs. Crack movement also occurs perpendicular or normal to the plane of the wall. This paper will examine and compare the in-plane and out-of-plane (normal) response of cracks in two different residences near limestone quarries. In two locations, sensors that measure in-plane and normal displacement were installed side-by-side on the same crack, allowing direct comparison of the two modes of response. In a third location, a perpendicular pair of displacement sensors was installed in a corner of a room to observe the bidirectional response of the structure at a corner. Both long-term and dynamic data were recorded with the same sensors; temperature, humidity, and air over pressures were also recorded to compare blast and weather effects. Measurements show that ratios of out of plane to in plane response to dynamic events can vary. However, the ratios of out of plane (normal) response to vibratory events to that of climatological change is still as small as the ratio for in plane crack responses.

Jan 1, 2010

By Catherine T. Aimone-Martin, Elena Oana Jacobs, Brent Meins

Accurate pressure measurements during underwater detonations are critical for the protection of structures and mitigating impacts to fish and marine mammals. Current guidelines that limit underwater pressures are based on past studies, many of which used sample rates of 48 and 65 kS/s (48,000 and 65,000 samples per second). These sample rates may be insufficient to accurately record high frequency, sharp rise time blast pressures. As such, pressure thresholds associated with fish and marine mammal injury or mortality may be underestimated, calling into question the pressure and sound pressure level guidelines that govern underwater blasting today.

Jan 1, 2019

By Joshua Hofman, Braden Lusk, Erin Morris

Explosions in urban environments, whether of accidental or malicious cause, often result in extensive injuries, loss of life, and property damage. The ability to predict the damage inflicted by these events is highly sought after; in order to predict damage, the behavior of blast waves within these environments must be quantified and understood. Urban constructs such as buildings and roadway intersections affect the natural propagation of a blast wave, intensifying or rarefying the wave depending on their arrangement.

Jan 1, 2012

By Martti Hagfors, Jussi Saavalainen

The underwater explosions has been used as a test method for the determination energy content of explosives. The test method is suitable for all kind of explosives; homogeneous, heterogeneous, wa-ter-resistant, no-water resistant, cap sensitive, booster sensitive, explosives with hard confinement, explosives without confinement etc. It is also the only test method by which shock, gas heave and to-tal energy values of the explosives can be measured separately. This feature makes it possible to use the test method to develop the explosives for different purposes; the military high explosives need more shock energy where as the gas heave energy is very important feature for the blasting and sea mine explosives.

Jan 1, 2010

By Joseph Hoang, Nick Reed, Scott Wishart, Michael Lovitt

Marvel Loch Underground forms part of St Barbara Limited’s Southern Cross Operations which is located 360km (224 miles) east of Perth. Southern Cross Operations produces approximately 120,000 ounces of gold each year. Mining occurs in over 8 lodes using a variety of stoping methods including Uphole Benching, Long Hole Open Stoping, and Core and Shell.

Jan 1, 2012

By Kurt B. Oakes, Brian M. Fortelka

Unimin Corporation operates an underground Silica Sand mine at Guion, AR located in North Central Arkansas. The Silica Sand deposit at Guion is part of the St. Peter Sandstone Formation, which is overlain by a competent dolomitic limestone from the Joachim formation, acting as the roof directly above. Both the St. Peter and the Joachirn Formations are of Middle Ordovician age.

Jan 1, 1999

By Francisco Sena Leite, Raquel Sobral, Vinicius Gouveia de Miranda, Céu Jesus

"The urgent need for improvements in the control and mitigation of environmental and social conditions associated with the extraction and processing of raw materials is increasingly a demand imposed by legal entities and institutions. Therefore, this present article proposes an improvement of the estimation in the magnitude of the vibrations resulting from rock blasting methodologies in the surrounding areas,incorporating the heterogeneity caused by uncontrollable parameters, such as geological andgeotechnical characteristics. This methodology combines the use of empirical vibration attenuation lawscommonly known and with terrain discretization techniques using Voronoi’s decomposition. For thevalidation assessment of this methodology, the data set collected and compiled is composed by 87 vibration measures collected in 16 sample points in one area of study of which 2/3 of the samples were used to create the model and 1/3 for the validation. Using normality tests for statistical residue analysis,it is possible to infer that this present model has null residual mean, as well as a smaller sum of residualerrors. Comparing the methodology present in this paper with the procedures executed nowadays, areduction of the errors associated with the estimation is obvious, highlighting a better characterization of the behavior of the vibrations associated with rock blasting."

Jan 1, 2017

By Lon Santis

This paper describes several applications of quantitative risk assessment in the management of commercial explosives operations. The Institute of Makers of Explosives’ (IME) quantitative risk assessment software modeling program IMESAFR was used for this analysis. Modeled activities include the unloading of a ship at port, locating a safe haven, and dealing with encroachment on a manufacturing facility. The layout of actual explosives sites were used for the analysis. The risk of fatality is analyzed and shown it can be used to make informed operational decisions for each activity. A study of the risks to individuals from activities involving commercial explosives compared to individual risks from other daily activities or exposures is also presented.

Jan 1, 2008

By Jorge Cárdenas Miranda, Hector Espinoza

Currently in open pit mining in Peru with double bench, it is a challenge to optimize fragmentation in the drill rows near to the slopes to ensure the performance in the loading and haulage operation along with the process in the plant. That is why the present paper addresses a previously unanalyzed variable on the effect of the discontinuity plane on the fragmentation results. From the numerical mathematical models applied through algorithms in advanced computational tools such as Elfen, it was quantified the improvement in fragmentation results as P80 through a correct pre-split plane both in its extension as well as in its width. The first results show an improvement of 30% in the P80 and ensuring the quality of the walls without damage to the matrix of the final wall. The basis developed in this paper is based on the concept of wave reflection in the free face zones where greater efforts are presented for fragmentation, a similar theory is presented in the variation of initiation sequences that seek a greater area of reflective planes in the form of "V". Cases were evaluated with a percentage of compliance of the pre-split planes from 0 to 100% evaluating the impact on the results and correlated with field information explaining the behavior and validating the benefit. From the quantification of the benefits, this work opens the possibility of focusing resources on optimizing the pre-split process to achieve an improvement in the fragmentation results, giving a greater tool in the decision to optimize the blasting process.

Feb 6, 2023

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 David Kosnik

This paper describes the technology and methods deployed in the continuous autonomous remote monitoring of cracks in interior and exterior walls of a residence near a limestone quarry. The objective is to quantitatively compare crack response due to blast-induced ground motion to that induced by diurnal temperature changes, weather fronts, occupant activity, and other phenomena. The remote monitoring and communication technology developed to obtain and disseminate crack response data for this study may provide the means to mitigate the effect of public concerns about potential impacts of ground vibrations inherent in construction and production of raw materials; it is critical to address these concerns because subsequent litigation may result in delays and increased costs.

Jan 1, 2009

By B. Winterberg, C. Lewis, M. Starkel, C. Johnson

Non-electric systems, specifically shock tube, have become the pyrotechnic detonator of choice over electric due to their safety regarding accidental initiation from stray radio signals. Typically, the best practice when hooking up shock tube systems is to have direct contact to ensure initiation. When gaps are introduced to the explosives chain, there is potential for detonation to come to a halt. It is understood that direct coupling is required between the various elements in the explosive chain to ensure detonation. This holds true whether tying in non-electric detonators, loading holes in a mining related blast, or priming a block of C-4. Poor contact and gaps in the explosives chain can lead to detonators firing out sequence, leading to increased vibration, air overpressure, and other undesirable blast results. Furthering work conducted in previous experimentation, a new study was conducted at the Missouri University of Science and Technology’s Experimental Mine in Rolla, Missouri to observe the initiation potential of an air gap and fragmentation on non-electric shock tube. A series of small test blasts were conducted using 50 grain detonating cord and fragments from a blasting cap to initiate a non-electric shock tube across an air gap of varying distances. The data collected in the high-speed imagery was used to analyze the velocity of the pressure fronts and blasting cap fragments used to initiate non-electric shock tubes across an air gap. It was found that the shock tube was sensitive to 50 grain det cord at a 5cm (1.97in) distance while parallel and 10cm (3.94in) when perpendicular as well as sensitive to frag from the electric cap out to 2.4m (7.87ft).

Jan 1, 2024

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 Ulrich Leiste, David M. Fox

This paper presents the results from small scale testing aimed at measuring the loads on a rigid target due to the detonation of a buried mine. The aim of this research is to find how the impulse delivered to the target varies as the air filled void volume fraction within the soil changes.

Jan 1, 2013

By Javier Illanes, Felipe Moroni

In recent years, implementation of Artificial Intelligence and Machine Learning model technology has gained ground in almost every aspect of human activities. The mining industry has not been foreign to these applications, with advantages including the creation of new optimization methods and the elimination of repetitive tasks. Those applications have been implemented in multiple operative areas, from preventive conveyor belt maintenance to energy optimization for minimizing environmental impact. The blasting process aims to use the energy liberated by the detonation of explosives to break the rock mass according to specifications that facilitate the comminution process. To optimize this process, the energy delivered must correspond to the necessary amount to exceed the tensional and compressional resistance of the rock mass. If the energy applied is insufficient, the rock will not reach the desired fragmentation level and the processing plant may incur additional costs. On the other hand, if the energy level required is exceeded, we incur increased blasting costs that correspond to excess explosive used. Optimization of this aspect of the mining process has major impact in the processing chain reflected in lower costs, efficient resources consumption and environmental impact. The Design for Outcome technology (DfO), developed by Orica, is used to characterize the rock mass in detail to classify, borehole by borehole, the rock mass relative hardness to deliver the adequate energy level to achieve optimal fragmentation. This technology uses information collected by drill sensors, producing data typically referred to as Measure While Drilling (MWD) data to classify the rock mass into domains that can later be used to apply optimal blast designs. In DfO, the data flow is fully automated, starting with the data produced by the drilling system and uploaded to the cloud, which is then domained using Machine Learning (ML) techniques, and then published for consumption using a web interface. Automated explosives loading rules are then generated for each rock mass domain, ensuring that for each borehole, the adequate explosive energy is delivered to achieve the desired fragmentation results with unprecedented accuracy. The application of machine learning techniques allows us to optimize the blasting process results by leveraging a deeper understanding of the rock mass. Applying these optimization techniques, we obtain considerable economic benefits, decrease resources consumption, and achieve a more sustainable mining operation. The application of DfO in a Chilean mining operation allowed the characterization of their rock mass into four domains and established specific explosive loading rules for each one. A 60kUSD reduction in explosives cost was achieved during the test period, while maintaining the desired fragmentation results and expected dig rate. These outcomes were the result of a comparison between the blasting costs used applying the technology mentioned above and a “traditional” classification of the rock mass with the corresponding blasting practices.

Jan 21, 2025

By Patrick Cahill, Jacob Miller, Nolan Mundwiller, Catherine Johnson

"The Experimental Mine at the Missouri University of Science and Technology is undergoing major developments. The underground workings are being expanded to include a ramp down to a second level which will comprise of larger opening and room sizes to better simulate modern mine layouts. Thisexpansion will enable the Experimental Mine to be utilized for many more generations. In addition, the new 15,000 sq. ft. Kennedy Mine Building is being constructed and will house the mine office,classrooms, and three laboratories to accommodate the mining and explosives engineering programs’ ever-increasing enrollment. With these new developments come an increasing need for safety and awareness in regards to explosives and blasting. This paper will utilize the Institute of ExplosivesMakers Safety Analysis of Risk (IMESAFR) software tool, to assess current magazine compliance withthe increased personnel limits and mine building location. Furthermore, this paper will assess theimplementation of a wireless blast warning system consisting of warning beacons and a centrally located siren which will be integrated with the construction of the Kennedy Mine Building. This warning system will provide the necessary precautions to safely conduct blasting-related experiential learningopportunities and research projects, and will enable facility staff to more efficiently oversee blastingoperations at the Experimental Mine. "

Jan 1, 2017

By Huang Daguang, Paulo Couceiro, Juan Navarro

Mining is typically conducted through a set of interdependent unit-operations, which commonly include drilling, blasting, digging and hauling, in order to deliver the required ore material into the comminution circuit and to remove waste rock with minimum impact in the operation. In such complex environment, the identification of critical paths, and respective interfaces between different unit-operations, are necessary to determine a sustainable long-term operational program. Facing this challenge, adaptive cost optimization strategies are required to increase productivity and revenue while minimizing potential environmental impacts. Since the overall mining efficiency can be strongly impacted by blasting outcomes, an operating method based on the searching of the ideal blast design is required in order to minimize the mine total cost of ownership. The implementation of a consistent continuous improvement program requires specific care in terms of design, control and execution of the different stages of blasting. For that, the application of the most advanced technologies for rock characterization, based on drill monitoring systems, and smart explosive products, allows the improvement and control of blast results by adapting the explosive energy distribution to the rock condition, so as to optimize the performance of downstream stages such as digging, hauling and comminution. This paper describes the application of a heuristic optimization approach, where blast parameters are used as decision variables to evaluate the potential impact of several blasting scenarios on subsequent unit operations, under the continuous ability of modelling, measuring and calibrating operational performances along of the mine cycle.

Feb 6, 2023

By Richard J. Mainiero, Harry C. Verakis, John J. Mulhern

There are application in coal mines where it would be advantageous from a safety stand point to fire unconfined shots. However, the firing of mud caps (adobes) or other unconfined explosive charges in underground coal mines is not permitted because of the explosion hazards associated with methane gas and coal dust. Present safety regulations in Title 30, Code of Federal Regulations prohibit such Practices. Recently, MSHA proposed revised coal mine regulations for the approval and use of sheathed explosives for Public comment.

Jan 1, 1987

By A. Ravi Kumar

A trench is a structure to accommodate fluid carrying pipelines for water, gas, petroleum products etc. Trench serves the purpose to haul the fluids in bulk over long distances safely and economically. Use of pipeline for moving oil and gas was essentially a post World War II development, but now it has acquired its own importance.

Jan 1, 2008