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By Steve Dillingham

A blast site incident has just occurred. Tensions are high, and, as the blaster, you’re in charge of the crisis at hand. Your mind is reeling, your thoughts frantic. The main areas of concern for you at the scene are to deal with immediate problems...aid the injured, take a head count, assess the damage, call emergency response, contact company headquarters, calm the neighbors, update your customer, and respond to the press on site. You feel as if all the bases have been covered...but, then again, have they? One of the biggest mistakes blasters and their companies can make is not including their Insurance carrier in the critical on-site accident procedures and emergency call list. Unfortunately, many companies believe that they are immune to the perils that can often, within a matter of minutes, create chaos that only happens to someone else.

Jan 1, 2002

By Brian Sandhuas, Robert McClure

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 North American 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 Felix Degold, Mark Ganster

Achieving a customer optimized fragmentation by using robust data from new technologies e.g. GPS positions of boreholes, fragmentation analysis to calibrate the geology and fragmentation prediction models. The inclusion of the collected data into the blast’s design makes it possible to accomplish a desired particle size distribution.

Feb 1, 2020

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 Robert Hopler

Torpedoing Wells. – On the completion of the drilling, or when the production is found to decrease, it is usual to “torpedo” the well to increase the flow. This process was patented in 1862 by Colonel Roberts, who believed, with many others, that the oil was contained in crevices in the rock, which might not have been tapped by the bore-hole. He therefore proposed the use of nitroglycerine, gunpowder, or other explosive, to break up the rock at the bottom of the well, so that these rich “pockets” might be brought into communication with the well.

Jan 1, 2007

By Roger Holmberg, William Hustrulid

Swedish cautious blasting techniques were used to excavate a room at the CSM Experimental Mine in Idaho Springs, Colorado,as part of a ONWI/DOE sponsored nuclear waste disposal research program.

Jan 1, 1981

By Dr. Calvin J. Konya, Anthony Konya

Blast violence has always been a criteria that has been analyzed without a quantitative approach relying on opinions of those viewing the blast and oftentimes does not transfer between open-pit mines, quarries, and construction projects. Added to this confusion is that on many regulate projects, such as U.S. Army Corp of Engineers construction projects, the definition of "flyrock" or violence can vary, and contractors must be able to meet this requirement. This project analyzed hundreds of blasts from various construction projects to develop a new metric to determine blast violence - the Violence Factor.

Feb 1, 2020

By A. Vishwakarma, V. Himanshu, K. Dey

Underground mining is the most feasible method after extinction of shallow depth ore deposits. Longhole stoping method is the most technically advanced method for the faster excavation. In this method, the holes are drilled in the form of ring pattern and explosives are used for the rock breakage. During blasting, the explosive energy sometimes also breaks the non-ore material. The non-ore material gets included in the extracted ore and enhances the ore dilution. Few uncontrollable factors which affects the ore dilution are ore body characteristics, rock quality, insitu stress condition etc. Apart from uncontrollable factors, explosive energy and blast design also plays an immense role in ore dilution. In the blasting practice, the purpose is to effectively utilise the explosive energy for rock breakage. The optimum delay is required so that the blast holes attain adequate free face before the blasting. This paper deals with the optimisation of blast design parameters to reduce ore dilution in underground hard rock mining having narrow vein. The study was carried out using numerical simulation. The explicit dynamics based modeller of Ansys was used for this purpose. The parametric variations in the models were done to optimise the parameters. The burden has been optimised first by varying the width of the narrow vein. The blasts of a ring consisting of single hole were conducted in the model by varying the width of the narrow vein. The damage contour under different parametric variations were analysed. The experimental trial has been also carried out at Zawar Group of Mine, Rajasthan, India. The optimum parameter was decided based on the result of experimental trial and numerical simulation model. The output of the model shows that optimum burden for 3.5 m narrow vein width is 1.12 m and for 1.0 m, it is 1.54 m. This shows that the optimised burden is higher in the vein having lesser width as compared to the greater width. The presence of joints/changed media/interface (between the sidewall and narrow vein) is the major reason behind this. The wave gets reflected back very fast on coming in contact with joints in a 1.0 m narrow vein as compared to a 4.0 m narrow vein. This will quickly convert the compressive wave into tensile wave giving rise to tensile slabbing. Hence proper utilisation of explosive energy will take place for the breakage of rock mass when the width of the narrow vein is smaller. The burden obtained from the experimental trial and numerical simulation models is less than 2.0 %. Hence the numerical simulation based approach can be used for the assessment of the optimum burden for ring blasting in narrow vein under different geomining conditions. This helped in reducing ore dilution and maximization of ore recovery. In the future, empirical relationships may be developed by considering different geological discontinuity, the strength of the rock mass and explosive parameters.

Jan 1, 2024

By Hairong Zeng, Matthew Baumann, Shahram Tafazoli, Edmond Chow

Measurement of rock fragmentation has evolved from a completely subjective and manual process to a statistically objective and semi-automated process. However, ultimately, the vision is to achieve a statistically representative and fully-automated process. From the blast optimization perspective, it is critical to receive reliable rock fragmentation results quickly to incorporate into the planning of subsequent blasts. Since manual rock fragmentation measurement methods tend to be time consuming, a fully-automated method is the practical way to meet these requirements.

Jan 1, 2012

By D. Scott Scovira, Remi Proulx

The Meikle Mine is a high grade, underground gold mine utilizing primary-secondary longhole open stoping with delayed backfill to produce 3000 stpd of ore. Hot and reactive ground conditions were encountered early on in the mine life. Ground temperatures up to 330” F were measured. In the early stages of mining, the mine experienced premature detonations using different explosives. The learning curve to safely mine this high-grade gold deposit in hot and severely reactive ground was indeed very steep. Currently, the Meikle Mine uses a special buffered bulk emulsion in all blasts to address hot and reactive ground concerns. In addition, exacting procedures are also followed to ensure safe work with explosives. The combination of new explosives technology and strict loading procedures permits high mine productivity with the highest degree of safety.

Jan 1, 2000

By Dr. Calvin J. Konya, Anthony Konya

Blast violence has always been a criteria that has been analyzed without a quantitative approach relying on opinions of those viewing the blast and oftentimes does not transfer between open-pit mines, quarries, and construction projects. Added to this confusion is that on many regulate projects, such as U.S. Army Corp of Engineers construction projects, the definition of "flyrock" or violence can vary, and contractors must be able to meet this requirement. This project analyzed hundreds of blasts from various construction projects to develop a new metric to determine blast violence - the Violence Factor. If a blast is fired using 1.25" (32 mm) diameter product and a 10-foot (3 m) bench, vertical uplift of 60 feet (18.3 m) would be considered extreme and violent by any professional in the industry. However, a 100-foot-high (30.5 m) bench using 12" (305 mm) bulk product, having a vertical displacement of 60 feet(18.3 m)might be considered typical or non-worrisome. This is where violence factor is beneficial as itprovides a system of scaling the violence of a blast based on the bench height to give manager a keyperformance indicator (KPI) which is easy to monitor and can provide a large amount of information onsite-specific design variables for their performance on blasting and the end-results of the blast. The Violence Factor of a blast is an integer which is scaled to determine how high vertical uplift of a blast is compared to the bench height. This project analyzed numerous blasts to determine what blast design variables contribute to violence. This violence has also been shown to occur when a non-optimal breakage mechanism, cratering, occurs and the design criteria that lead to this cratering. Finally, this paper will present typical results of various levels of violence including backbreak, fragmentation, and muckpile configuration.

By Jason Baird, Braden Lusk, Dominique Nolan, Allen Stults

Conical shaped charges have been used to penetrate rock for many years now. Examinations have been made looking at shaped charge liner geometry, material, and standoff, as well as explosive composition, confinement and initiation. Most of the testing conducted towards penetration rather than cratering has fallen within the realm of the petroleum industry and as such been confined to specific rock types, with test apparatus that include simulated down hole (subterranean) environments. The testing conducted within this experimentation is conducted at ground level, in small scale samples, using a single standoff, against multiple rock types. The data collected from that testing is examined here and relationships between physical properties of the rock and the liner are analyzed. The analysis of that data raises the possibility of a relationship that may lead to new empirical methods of penetration prediction in rock.

Jan 1, 2012

By Larry Ng, Keith McDonald

The benefits of controlled blasting techniques have gained increasing recognition by the mining industry in recent years. The utilization of an effective controlled blasting programme can result in a safe work environment with less loose rock and a reduced level of scaling and ground support.

Jan 1, 1994

By Ricardo Dr. Chavez, Mathieu Lachamp, Rob Dr. Farnfield

Pueblo Viejo is an open pit gold mine in the Dominican Republic which is always looking forward to implement the newest technology in the industry to improve all processes. Focusing on one of the pillars of the department and our company, digitalization, we’ve been looking for the technologies that allow us the automation of data generation, supervision and process innovation. That’s where a new Drill and Blast software takes place, helping to integrate the process from the beginning to end, right after the pattern is designed until it’s blasted, allowing us to track results like vibration, fragmentation, performance, cost and inventory of each blast in a single platform. The software helps engineers to generate back analysis by blast, bench, pit, month and many other ways, in a timely friendly manner. Therefore, we can catch business opportunities and improvement for the drilling and blasting process.

Jan 1, 2019

By Douglas Bartley

As the economy continues to slowly recover, our industry continues to finds ways to increase productivity while being forced to cut costs. The drilling and blasting process is the starting point of any aggregate or mining process. Many people refer to it as the “Primary Crusher” as it will always be more efficient to crush rock with explosives energy than it will be mechanical energy. It is the more efficient use of this energy that is addressed in this paper.

Jan 1, 2012

By Jorge Blázquez, Paulo Couceiro, Patricio Vergara, Luis Martínez, Juan Navarro

This study introduces the X-2Mill solution, a refined two-step methodology aimed at optimizing blast designs by aligning explosive energy with rock properties. The approach employs the X-4Traits Model, which uses drill-monitoring data from both autonomous and manual drilling modes to develop two critical indexes: the Drilling Rock Factor (DRF) and the Drilling SAG Power Index (DSPI). The DRF integrates the Size-Energy Fan Model with rock fragmentation results and blast design parameters, while the DSPI adjusts Specific SAG Energy (SESAG) based on Bond’s theory, incorporating ore X80 results, SAG mill capacity (TPH), and power draw to estimate milling difficulty. To enhance prediction accuracy, the X-2Mill solution incorporates, to a Principal Component Analysis of the normalized drilling data, a Meta Machine Learning model with a 3D spatial function, accounting for information from surrounding drill holes. This integration improves the precision of the DRF and DSPI estimates. The methodology unfolds in two main steps: Step 1: Bench-Scale Pattern Design, involves defining the target P80 size for ore based on the SESAG and the DSPI. It also establishes target X80 sizes for waste and oxide materials and iterates to determine the optimal Burden x Spacing (BxS) using the Size-Energy Fan Model and the DRF. Step 2: Blast-Scale Selective Explosive Density/Energy focuses on refining explosive density on a hole-by-hole basis to achieve the specified X80 values for ore, waste, and oxide materials. The X-2Mill Solution was developed at Minera Escondida Limitada (MEL) using data from 162,761 blastholes across 356 blasts conducted over three mine expansions. This solution addresses the challenges of blasting harder and more difficult rock, particularly in the lower levels of the mine. By adapting the blast pattern and explosive density to the specific rock properties and ore/waste designation, the X-2Mill Solution aims to achieve precise size distributions and improve overall blasting performance. The results demonstrate that the X-2Mill Solution balances ore fragmentation to meet SAG mill throughput requirements while optimizing powder factor costs for waste material and maintaining digging efficiency. By efficiently distributing explosive energy, the solution not only enhances throughput but also improves blasting efficiency while ensuring stable slopes and minimizing fault activation.

Jan 21, 2025

By B Mohanty

Full-face blasting rounds have been used to excavate a 4.6-mdiameter shaft at Atomic Energy of Canada Limited's Underground Research Laboratory near Pinawa, Manitoba. Both standard pyrotechnic delay detonators and the newly developed electronic delay detonators (EDD) were used on the project. The full-face blasting technique, employing 89-mm-diameter relief holes and 38-mm diameter blast holes, NG-based explosives, and the regular long period delay detonators, has been standard practice at the site, giving excellent wall control and fragmentation results. The comparison blasts using pyrotechnic detonators and EDDs were carried out to test the operational logistics, timing accuracy and blast results obtained with the latter. The long period pyrotechnic delays ranged from O to 18, with the nominal delay varying between 350 ms and 800 ms. The EDD blasts used the same number of periods, with the respective delay interval between successive periods set precisely at 190 ms and 210 ms for the two blasts. Based on a broad range of critically assessed parameters, the EDD blast results proved to be signficantly superior to those obtained with regular pyrotechnic detonators. The results have been analyzed in detail and the relative merits of the two delay systems have been determined. Alternative designs to derive maximum benefits from EDDs in shaft and tunnel blasts have also been suggested.

Jan 1, 1990

By Rakesh Raghavaraju, Bibhu Mohanty

Prediction of fracture and fragmentation characteristics of a rock mass subjected to dynamic loads, such as in blasting remains a major technical challenge. The present study is aimed at characterizing the shock transmission properties in controlled experiments in small scale in a well-characterized granitic rock, under varying borehole coupling conditions. Single blast-hole tests were conducted in a granitic rock sample of 145 mm (5.7 inches) diameter and height. The boreholes (in two diameters: 6.4 mm (1/4 inch) or 9.5 mm (3/8 inch)) were loaded with detonating cord of varying charge weight (5.3 g/m or 25 grains/ft to 31.8 g/m or 150 grains/ft of PETN). The effect of explosion gas penetration into the target rock was eliminated by inserting a thin-walled copper liner along the borehole wall. Embedded carbon composite resisters were employed at varying distances from the borehole to measure transmitted shock pressure for two coupling conditions (i.e. air and water) at distances of 1x to 9x the borehole diameter. The paper analyzes the decay of shock pressure as a function of distance from the borehole, and its implication on shock-induced fracture properties of the target rock as the first step in predicting fracture and fragmentation behaviour in a well-characterized rock.

By Mark S. Stagg, David E. Siskind

The Bureau of Mines arranged to have a wood-frame test house built in the pat of an advancing surface coal nine so it could investigate the effects of repeated blasting on a residential house. Structural fatigue and damage were assessed over a 2-yr period. The house was subjected to vibrations from 587 production blasts with particle velocities that varied from 0.10 to 6.94 in/s. Later, the entire house was mechanically shaken to produce fatigue cracking. Failure strain characteristics of construction materials were evaluated as a basis for comparing strains induced by blasting and shaker loading to those induced by weather and household activities. Cosmetic or hairline cracks 0.01 to 0.10 mm wide occurred during construction of the house and also during periods when no blasts were detonated. The formation of cosmetic cracks increased from 0.3 to 1.0 cracks per week when ground motions exceeded 1.0 in/s. Human activity and changes in temperature and humidity caused strains in walls that were equivalent to those produced by ground motions up to 1.2 in/s. When the entire structure was mechanically shaken, the first wallboard tape joint crack appeared after 56,000 cycles, the equivalent of 28 yr of shaking by blast-generated ground motions of 0.5 in/s twice a day.

Jan 1, 1985

By Joseph Indeck, Seokbin Lim, Andrew Thompson

In the design of explosively driven penetration devices, understanding the impact conditions between the explosively propelled penetrator and the target is one of the most important steps in optimizing the performance of the device. These impact conditions are especially prevalent when a shaped charge jet impacts concrete, which is not an ideal target material. The specific impact conditions, including but not limited to the impact angle and jet properties, create a great deal of variability that affects the performance and penetration of the shaped charge. The large amount of impurities and voids in concrete, along with its heterogeneous nature and the general strength characteristics, make concrete a non-ideal material for shaped charge jet penetration. These material characteristics lead to a highly non-linear deformation behavior of the concrete target during a hyper-velocity impact.

Jan 1, 2011