Search Documents

By Francis Otuonye

Rock fragmentation by blasting still remains the most common and cost-effective method of excavating hard rock in mining and tunneling operations. During blasting, the dynamic stresses induced by the detonation of the explosive, in addition to fragmenting the rock in the vicinity of the blast, may fracture the rock at considerable distances from the point of detonation of the explosive. The fractures can result in reduced mine safety, increased costs to support the opening, low productivity and perhaps high ore dilution. Besides the dynamic stresses produced in the rock, air blast overpressure pulses are generated and propagate through the network of underground mine openings. The waves, unable to spread out spherically or hemispherically like blast waves from surface blasting, are forced to propagate by reflection from the roof, ribs and floor down the drift. Blast wave focusing can occur and produce intense shock waves that could damage ventilation barriers such as cement block stoppings.

Jan 1, 1992

By Mauritz Kotze, Jason Furtney, Ewan Sellers, Sandy Etchells, Tom Szendrei

The development of a simple model for gas flow and burden movement has driven the need to improve our understanding of burden breakage mechanisms for single hole blasts and the interaction between multiple holes in solid and jointed rock masses. Conventional analytical understandings of the burden breakout using the elastic-tensile fracture model were studied and found to provide a breakout angle that is independent of burden in contradiction to experimental data. By considering rock fracture in terms of Mohr-Coulomb plasticity using analytical expressions from the field of cavity expansion analysis an improved relationship between breakout angle and burden is derived until the point of critical breakout at which the angle of breakout suddenly changes from between 90 degree and 100 degrees to zero. This suggests that the critical burden occurs at about 0.6 times the radial fracture zone calculated from the analytical solutions.

Jan 1, 2013

By Robert Hopler

BH Note: This price list stresses the point that the number six strength cap should be used with all high explosives. It’s interesting that duPont chose to continue to supply the lesser strength caps – but lowered the price of the #5 or #6 to be closer to that of the #4 and #3. There were imports of the lower strength caps at the time that had to be competed against, hence the price reductions. Another interesting point on this price list is the noting on the “Red Cross Explosives” page that these explosives reduce the danger incurred during the operation of thawing. As noted many times in these articles, this problem was not to be solved for about another 16 years or so.

Jan 1, 2011

By Carlos Enrique Arroyo Ortiz, Jadir Pedro Alves

This paper presents some of the results obtained during the research work about the use of technologies and digital transformation in the process of rock drilling in open pit mines. The use of automation presents itself as a disruptive factor and a driver of improvements that provide sustainability in rock drilling. Seven main operational parameters were utilized to combine measurement while the drilling (MWD) with other information generated by the equipment during hole drilling, in six different lithologies in an iron mine, located in the central region of Minas Gerais in Brazil. Adjustments and corrections were made to the data collected in order to minimize external influences other than the rock itself, to ensure the effectiveness of the analyses. Finally, we sought to compare the performance of the drilling process in manual and automatic operation modes. Thus, making it possible to show the efficiency and impact on the sustainability of rock drilling operations in open pit mines.

Feb 6, 2023

By John Hutchings

Drilling and blasting is a clearly delineated work process, which has well defined inputs and outputs. Drilling and blasting is also a process with a number of steps each of which has measurable outcomes. Drilling and blasting is ideally suited to the application of Total Quality Management principles. Most drilling and blasting information is generally poorly managed with disjointed and unrelated Information Technology systems managing parts drilling and blasting data. Data is often moved from on system to another, sometimes manually. In the field, drilling and blasting is still very much a paper based system and which has not generally benefited from some of the recent hardware and software technology advancements now “on the shelf”. Data collected on paper rarely is transcribed back into an electronic system for further analysis. It is often difficult to collate or review historic drilling and blasting data. This paper will present a definition of Total Quality Management and demonstrate how it can be applied to the drilling and blasting work process. Total Quality Management defines the mechanisms for the application of continuous improvement to drilling and blasting. Continuous improvement will provide opportunities to modify drilling and blasting work process outcomes and generate real cost benefits within the overall mining process. A complete drilling and blasting management system frame work, called DBS, is presented in this paper. DBS provides all the components necessary to implement a full drilling and blasting Total Quality Management solution. Also highlighted will be appropriate “off the shelf” technology that can be applied to replace current paper based systems and provide the means to connect with other mine data systems. Various examples will be discussed which will demonstrate potential benefits of applying a structured Total Quality Management approach to a drilling and blasting work process.

Jan 1, 2004

By Christoph Muller, Geoffrey Liggins, Mohan Hensman

Modern commercial blasting is as much a technical process as it is a business one. As with most processes both aspects of blasting are driven by and generate new data. The time-critical nature of commercial blasting in mining and construction projects, dictate the timely exchange of information so as not to impede production or commerce. Up-to-date information about the blast to be undertaken can help suppliers: meet customers’ expectations to address challenging ground conditions; react to a market where quickly changing orders occur regularly; and address as-drilled blast patterns as opposed to baseline plans. “Real-time” data exchange into and out of the blasting process supports the whole-of-mine data management that the industry is migrating to.

Jan 1, 2010

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 Mark S. Stagg, Rolfe E. Otterness, Stephen A. Rholl

The Bureau of Mines fired seven test blasts in a 22-ft bench of limestone, screening the material to investigate the influence of explosive type and between row delays on fragmentation. Four 4-hole, single-row test shots were conducted evaluating dynamite, ANFO, emulsion, and a 60-40 emulsion-ANFO mix. Three 12-hole shots, with three rows of 4-holes, evaluated delays between rows of 24, 36, and 120 ms. Accurate in-hole electronic delays were used, firing within 1.5-ms of the nominal delay. All seven shots had a 6- to 7-ft burden, 10-ft spacing, with a hole diameter of 3-1/2 in fired on a 12-ms delay between holes in the row. The tests were instrumented with strain gauges grouted in the burden region examining stress wave and gas pressure effects. Fiber optic probes were used to confirm timing and to obtain detonation velocities.

Jan 1, 1989

By R. Jacob Cefalo, Miguel Valenzuela

The modern drill and blast engineer operates in an environment often rich with data from drilling data and blast designs vs. actuals to fragmentation distributions and vibration records. Despite this abundance, much of the information generated remains underutilized, often collected as a matter of routine rather than for a means to an end. This paper explores how artificial intelligence (AI) can bridge that gap, transforming raw operational information into actionable insights that lead to more consistent and optimized blasting outcomes. Through AI-driven analysis of drilling logs, burden and spacing measurements in design vs. actual, fragmentation distributions, and vibration records, we can identify hidden patterns and correlations that traditional analytics overlook or that we may not be aware of. These insights enable engineers to proactively adjust designs and loading strategies, ultimately improving performance aspects such as improving fragmentation, minimizing ground vibration, and lowering overall operational costs. The paper examines the industry's reliance on lagging indicators, such as post-blast fragmentation surveys or actual powder factors, and suggests the need to shift toward leading indicators like real-time drill data monitoring and predictive fragmentation modeling. Utilizing AI to forecast outcomes before a blast is carried out allows engineers to take corrective actions early in the process, thereby creating a feedback loop that continuously improves performance. This integration of AI into drilling and blasting practices marks a pivotal opportunity for the explosives engineering field to evolve from reactive to predictive methodologies unlocking a new level of operational intelligence and value creation.

Jan 26, 2026

By Sharon K. Reamer, Klaus G. Hinzen

A series of controlled seismic experiments was performed in a limestone quarry in southern Germany to study seismic effects of cylindrical charges fired in both a half space (HS) (burden 63 m) and quarter space (QS) (burdens of 3 and 3.5 m) geometry. Charge columns contained from 20-32 kg of explosives and initiated from the bottom. The explosives formed a cylinder 4 m (20 kg) and 5 m (32 kg) high and 90 mm in diameter at depths from 3-8 m below ground level. Prior to each of the larger explosions, small charges of 0.12 kg seismogelit were fired at 4 m and 8 m depths in the same boreholes. Seismograms were obtained from 23 three component surface stations and up to 10 three component borehole stations (6 m depth). For each experiment, stations were located on three linear profiles of length 72 m at different azimuths from the source and one semicircular profile at a constant range of 30 m.

Jan 1, 1991

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 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 Donna Kliche, Charles Kliche

It has been previously documented that various weather conditions such as wind direction and speed, cloud cover and, especially, temperature inversions can significantly affect the overpressure generated by a blast event (Siskind et al, 1980; Oriard, 1999; Siskind, 2000). The overpressure can be magnified downwind and reduced upwind; a change in the regular profile of temperature with elevation can magnify or focus the sound intensity at some distance from the blast event.

Jan 1, 2011

By Calvin J. Konya

Backbreak behind the last row of boreholes can be a significant problem for blasting operations. Backbreak will interfere with the proper drilling and execution of the subsequent shot and can produce well defined boulders, which will not be broken by the subsequent shot. In order to determine the effect of timing on backbreak, a full scale blast with 6 1/2 inch boreholes was used to test the effects of timing. The test site was a quarry which had suffered from severe backbreak regardless of the blasting pattern or explosive used. One half of the production blast was loaded and initiated using the current technology at the quarry, the other half of the blast was deliberately timed in such a manner as to minimize backbreak. The timing was such to allow for ground movement in one row before the subsequent row fired. The test results proved that the amount of backbreak and flyrock could definitely be controlled with the selection of the proper borehole timing.

Jan 1, 1987

By David La Rosa, Matthew Craft, Lee Julian

Rules of thumb are ubiquitous in blasting. Typically presented as ratios, they assist with the initial assumptions of blast design and provide guidance for best practice. Examples include the blast hole diameter as a function of bench height, and stemming length as a function of hole diameter. The most common rules of thumb were developed in mid-20th century and it is important for a blaster to know if the rules of thumb are still reliable.

Feb 6, 2023

By Roy McKinstry, Mark Rantapaa, Thomas Bolles

In March of 2001 Barrick Goldstrike Mines, Inc. began evaluating the potential benefits of electronic detonators at the Betze Post open pit gold mine. The original evaluation focused on increased fragmentation, and excavator productivity. During the original evaluation there was an attempt to quantify mill throughput. Early tests indicated that there would be a benefit to mill throughput, however management was hesitant to take on the added cost of electronic detonators based on the initial evaluation. In early 2002 a decrease in mill throughput was being forecast as a result of harder ore being encountered. As a result of the initial electronic detonator evaluation a team of individuals from the Open Pit and Process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative. This initiative was targeted at improving mill throughput as the harder ores were encountered. Batch tests were conducted to determine if adjustments to drilling and blasting in the open pit could increase mill throughput and justify a 50% increase in drilling and blasting costs for the harder ore material.

Jan 1, 2004

By Lon D. Santis

The Code of Federal Regulations Title 30, Parts 56, 57, 75, and 77 require that detonators and explosives be separated by four inches of hardwood or equivalents when transported together in mines. This standard was developed to protect the explosives from initiation by the more sensitive detonators. The research reported here is an attempt to quantify the fire protection offered by four inches of red oak and other materials. Boxes with a volume of 6.75 cubic feet were made from four-inch thick rough green oak (RGO), two-inch thick RGO plied, two-inch thick #1 common (dried) red oak plied, and a metal/plywood composite. These and boxes meeting the Institute of Makers of Explosives' (IME) Safety Library Publication No. 22 were tested in bonfires. The boxes were instrumented with thermocouples, filled with detonators, and placed over a kerosene fire imparting about 16 kilowatts per square meter heat flux for up to 3 hours.

Jan 1, 1997

By Catherine T. Aimone

A series of experiments have been performed to characterize fragmentation and microcracking in quartz monzonite copper porphyry. The flyer plate impact method was used to generate plane shock waves in rock specimens for impact pressures between 1.6 and 7.3 GPa and impact pulse durations between 1.1 and 7.0 µs. The effects of pressures up to 4.8 GPa and pulse duration on fragment size distributions and microcrack densities were studied. The results show that pressures effect particle sizes to a greater extent at higher pulse durations. However, changes in pressure and pulse duration show little influence on the density of microcracks induced during explosive loading. These results indicate that the nucleation and growth of microcracks in rock subjected to shock waves occur uniformly throughout. A substantial decrease in particle sizes for high pulse durations is attributed to more time allowed for microcracks to grow and coalesce, forming individual particles.

Jan 1, 1985

By O Omidi

Selection of delay times to optimize fragmentation has been a controversial topic among researchers and blasting practitioners. This paper reviews previous experimental information and presents the results of new tests conducted in small blocks constructed using a commercial grout. The effect of the delay on the average fragment size, coarse fragmentation and uniformity of fragmentation is discussed. Fragmentation was coarser at extremely short or extremely long delays, while a fairly constant average size was obtained at a variety of intermediate delays. Uniformity, defined as the slope of the fragmentation distribution through the average fragment size, was poor at short and very long delays and relatively constant at the intermediate delays. Some tests attempted to minimize the effect of gas penetration by lining the boreholes with copper tubes. When this was the case average fragmentation changed marginally, while uniformity was significantly affected by delay and was typically smaller than in the unlined tests.

Jan 1, 2014

By Marion Smith, Thomas M. Keevin, Dennis G. Wright, Gregory L. Hempen, Joel B. Gaspin, Thomas L. Linton, Gregg R. Gitschlag

"A Natural Resources Working Group, within the International Society of Explosives Engineers, reviewed published environmental effects data, identified data gaps, and prioritized data collection needs relative to underwater explosive use. Six groups of organisms were reviewed: 1) aquatic plants, 2) aquatic invertebrates, 3) fish, 4) amphibians, 5) reptiles, and 6) marine mammals. Studyrecommendations included: conducting basic research to determine the relationship between pressure waveform and mortality where little or no data exist (e.g., aquatic plants, fish, amphibians, reptiles, and marine mammals) and conducting narrowly defined studies where adequate data have been acquired (e.g., aquatic invertebrates). The goals of the recommended studies are to develop the relationship between pressure waveform and mortality/damage in order to construct mortality models. Development of comprehensive mortality models would be extremely useful to the blasting community for assessing environmental impacts and developing strategies for reducing impacts from explosives used underwater."

Jan 1, 1999