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By Thomas Barkley

Mining tradition holds that a parallel round underground can not be any deeper than it’s smallest face dimension. ln other words, a mine using a 12’ (3.7 m) high by 24’ (7.3 m) wide room and pillar mine, the deepest pull that can be achieved is plus or minus 12’ (3.7 m). After experience with decking of rounds in a 12’ (3.7 m) diameter shaft to achieve more than 12’ (3.7 m) advance per round, the concept of deepening the pull on horizontal parallel rounds seemed to be a feasible concept. Tests were conducted in a conventional room and pillar metal mine with a round size of 12’ (3.7 m) high by 24’(7.3 m) wide. Standard rounds were drilled with a 16’ (4.9 m) steel as parallel rounds to an average depth of 14.5’ (4.4 m). The average depth of pull on these rounds was about 13’ (4.0 m). Using the available drilling equipment, 20’ (6.1 m) drill steel was used to drill holes to an average depth of 18’ (5.5 m). Five rounds were drilled and shot with a resulting aven$e pull of 16.2’ (4.9 m) or 90 % of drilled depth. Rounds were designed with decked bum cuts to maximize depth of pull in the cut area An innovative method of de&mining drilling accuraq was used to estimate it’s effect on depth of pull in the rounds. This method used a standard automatic 35-mm camera and scaling to determine the average drill deviation for many of the holes in the rounds.

Jan 1, 2000

By H. S. Venkatesh R. Balachander, G. C. Naveen

During the construction of a 1020 MW underground hydroelectric project in Bhutan a huge rock fall took place in the Downstream Surge Chamber (DSC) during March 2016. The total quantity of rock in the fall area is estimated to be about 1,50,000m3 (2.6 billion cubic feet), out of which about 25,000m3 (0.44 billion cubic feet) of muck was removed. The removal of muck was stopped apprehending that the cavity formed due to the rock fall may get further aggravated leading to widening and destabilising the adjacent transformer hall cavern or it might day light as the top cover was about 190m (623 feet). As the fall has virtually blocked the 314m (1030 feet) long cavern and divided it into two different chambers (south and north), and that the muck cannot be disturbed, it was decided to erect concrete wall on either side of the fall up to the cavern roof and then later address the filling of the cavity with appropriate fill material. As the access to the DSC was there for the southern side it was decided to extend a cable tunnel which was terminated at a distance on the north side of the cavern by D&B so that once it gets punctured into the north wall of the DSC it can be used to access the fall from this front too. This is a unique situation where in every blast approaching the DSC, the parting between them is diminishing and hence the tunnel blast will be exerting axial load on the parting wall leading to dynamic transient loading conditions and buckling may take place on the northern wall of DSC. This paper describes the various drill blast combinations adopted for successful excavation of this tunnel.

Jan 1, 2019

By Raden Haris Handayana, Jerri Mapanta, Eri Barlian, Milia Putri, Nasfryzal Carlo, Jihan Lubis

Waste oil is a growing problem throughout industries where environmentally responsible disposal ways are usually costly. There are many industries have developed process to reuse of waste oil as a source of energy on their own premises. Hanwha Mining Services Indonesia is one of blasting service that manufacturing explosive using waste oil. The usage of 60 % waste oil content in fuel solution already developed applied since 2020 at Petrosea-Kideco Site and will be increase until 100 % in 2022. The purpose of this research is to analyze the increasing of waste oil usage from 60 % to 100 % content at Petrosea Pit without reducing the emulsion quality and performance, and surely eliminate the fuel cost and reducing waste oil processing cost. Some trial conducted to determine the effect and quality of using 100 % waste oil content on emulsion at production blast. The method use to know the quality of 100% waste oil of emulsion is by direct application on bench blast. Using Microtrap VoD recorder, explosive energy will be recorded into m/s dimension, microtrap recorder the speed of explosive detonation in line with the speed of burning wire in the blast holes. The summarized of this research present that the using of 100 % waste oil content on emulsion can be applied on bench operation with the result of Velocity of Detonation (VoD) data is 4,559 mm/s, the mean of fragmentation size is in range 65.31 to 225.62 mm, the average of digging time on 1st layer is in range 10.2 to 11.6 s and on 2nd layer is in range 8.9 to 9.5 s, and the productivity still achieve on target. The result of all parameter quality still in the standard range of Hanwha and Petrosea.

Feb 6, 2023

By Bonifacio Degay, Mike Lovitt

PT Freeport Indonesia is a block cave mine that now utilizes an advanced undercut method to set up the min in the Deep Ore Zone (DOZ). In this method a slice of rock (undercut) is broken such that it sits on top of the drawbell level. The drawbells are developed to channel the broken ore into the extraction level and to enable the caving orebody to be drawn out in an even and controlled manner. These drawbells are difficult to form due to the small amount of void that can be developed in the low strength rock before firing. Starting with two rises of 2m square, the void ratio for the entire drawbell around 6%, which would normally result in a frozen and unproductive blast. Orica -Mining Services have worked with PT Freeport in a collaborative effort to find a solution to the mining problem. With excellent control of timing of the blasting it is possible to get fluid flow of blasted rock out of the draw points such that more void can be made available for blasting the remaining parts of the drawbell. The i-konTM electronic blasting system gives the exacting control of timing within the blast to achieve this Dynamic Void Generation (DVG). The solution stops the need to charge close to brows in the drawbells and reduces the cost and time related to developing initial blast voidage. This paper identifies the results of the trials including design, photographic evidence and vibration analysis. The flexibility and accurate timing of this electronic blasting system has enabled single hole initiation rather than 4 or more holes being initiated together, thereby reducing the damaging vibrations to the extraction level.

Jan 1, 2004

By Marcus Neves, Eventomar Junior, Adilson Castro, Leandro Silveira, Sérgio Augusto

The collapse of the Vale S.A. mining tailings dam in 2019, a tragic event that shook Brazil and the world, had consequences that transcended the immediate pain and devastation. Among them, the suspension of rock blasting activities in several mines in the Quadrilátero Ferrífero region of Minas Gerais, Brazil. This measure, taken as a precaution and with the aim of ensuring the safety of nearby geotechnical structures and the population, had a significant impact on the mining production chain. To overcome these challenges and resume blasting activities in a safe and sustainable manner, the mining industry has been dedicated to developing and improving solutions. One of the promising alternatives is the signature hole technique, used in conjunction with attenuation laws. The complex geology of the Quadrilátero Ferrífero, with lenses of compact ores immersed in friable materials, the presence of discontinuity families, and the emergence of geological faults, requires detailed analyses and specific adaptations of the signature hole technique and constant monitoring of the vibrations to calibrate the attenuation laws to ensure compliance with permissible limits and safety of the operations. To demonstrate the methodology, a case study in Abóboras Mine was described. Additionally, the challenge of achieving the desired level of production while controlling vibration and slope damage has driven the development of new charging and timing techniques. To address this challenge, a comprehensive approach was undertaken. A substantial database containing more than 4,000 registers of blasting-induced vibration events from 520 blasts was meticulously compiled from 2020 to 2023, 6 different attenuation laws were established and continuously calibrated with 99.3% of compliance regarding permissible limits of vibrations. The successful implementation of these actions allowed for the resumption of blasting, increasing production from 10 million metric tons to 43 million metric tons per year assuring sustainable operation.

Jan 21, 2025

By Gordon Revey

In construction and mining work, situations occasionally occur where hard rock or concrete must be excavated at locations near critical structures or utilities. Fearing damage from blasting, contractors and engineers often explore the viability of using mechanical methods or expansive concrete to facilitate the excavation work. However, for moderate to large excavations, the prolonged duration and high cost of using these methods is often impractical. In these situations, under the right conditions, controlled blasting and blast-management methods can be used to speed up the work and lessen costs. The process of determining whether or not blasting is practical is ofien complex, particularly when risks are high.

Jan 1, 2001

By Douglas Lindsey, Glenn Hazen, Shad Sargand

"With the innovation of computational equipment, an exact analysis of structures as dynamic systems is more approachable. Accordingly, the dynamic system can be established, if the natural characteristics such as the natural frequency and the damping fraction of a system are known. Through dynamic analysis, the response of a structure can be predicted from ground vibration, and it becomes possible to forecast the damage potential to the structure with reasonable accuracy. Most vibration will appear as single harmonic or superposition of waves that consists of several harmonics with different frequencies. A vibration signal can be expressed, therefore, as the function of sine waves. If a signal is periodic, the particular harmonic with the smallest frequency will befundamental and frequency of the others will be multiples of the fundamental frequency."

Jan 1, 1993

By N Vijay Mohan, K V. Balamukund, G Ananth Ramulu

Jointing of steel rods in reinforced concrete structures needs careful consideration as it renders the structure weak at the joint. The jointing is usually done at sections of structural members, where the bending moment and shear force are least. Jointing is done either by overlapping the rods or welding or by mechanical splicing. A novel method of jointing them is by inserting the two rods in a steel sleeve and cladding it on to the rods by subjecting the sleeve to explosive energy. A rod jointed in this fashion is tested for direct tension and bending when used in a reinforced concrete beam. The test results show that it is an effective method. The advantage is that a number of joints can be made in a single operation.

Jan 1, 1993

By Jane Wright, Brent Blanchard

Question: When it comes to demolition projects, what could be more demanding than asking a blaster to explosively demolish a stubby, heavily-reinforced concrete structure in the heart of a third-world country? Answer: Asking them to fell only half. Such was the charge recently put forth to Controlled Demolition Group (CDG), Yorkshire, UK when they were called to Casablanca, Morocco to provide a stunning demolition effect for the upcoming Universal Pictures film Spy Game, starring Robert Redford and Brad Pitt. Director Tony Scott (True Romance, Enemy of the State) contacted the renowned demolition firm after seeing their work on television and receiving recommendations from explosives manufacturers. The film’s producers then asked the CDG team if they could bring down half of an apartment block as part of a dramatic suicide bomber sequence.

Jan 1, 2002

By Martin Langenderfer, Sergii Chertopalov, Catherine Johnson, Vadym Mochalin, William Fahrenholtz

The high temperature and high pressure of an explosive detonation can be used for the production of nanomaterials. The controlled detonation of explosive compositions along with the collection and characterization of reaction products encompasses a process known as detonation synthesis. The primary advantage of the method of detonation synthesis is the possibility for producing monocrystalline nanoparticles with diameters of less than 10 nm. In order to successfully synthesize nanomaterials via the detonation process, it is necessary that the explosive detonation is conducted in a sealed environment. This environment when pulled to a vacuum or purged with inert gas such as argon will reduce the oxidation of detonation reaction products. Detonation synthesis testing is currently being conducted in a 1.8 cubic meters (m3) (64.3 cubic feet (ft3)) ellipsoidal pressure vessel consisting of two interlocking half shells. The testing involves the controlled detonation of cast mixtures of Cyclotrimethylene-trinitramine (RDX) and 2,4,6-Trinitrotoluene (TNT) in conjunction with siliceous compounds to produce nanocrystalline diamond and silicon carbide. Alternative detonation environments including the presence of a cooling medium such as water or dry ice to absorb residual, post detonation, thermal energy and enhance the stability of the materials being produced have improved yield. Modifications to the explosive charge composition have an effect on the type and quantity of materials that can be produced. Doping of explosive charges with various organic and inorganic compounds has shown promise in the synthesis of materials that are difficult or uneconomical to produce through other methods. This paper outlines the process development of detonation synthesis facilities. Preparation of the pressure vessel to create a suitable detonation environment for the production of nanomaterials is examined. Formulation of explosive charge compositions and considerations involving test charge initiation are discussed in detail. Experimental results and analysis from initial testing as well as plans for future research are also evaluated.

Jan 1, 2018

By D K. Joyce

Large diameter boreholes have become increasingly popular in underground mining. Drilling equipment can drill full rings, including vertical upholes. Special techniques are required to load upholes of three inch to eight inch diameter. The current methods for loading AN/FO and bulk or packaged emulsions are described.

Jan 1, 1988

By C Deacon, M Jones, P Duniam

Electronic blast timing has been in use around the world since the mid-eighties, and, whilst it has yet to be used commercially by large operations on an ongoing basis, significant inroads have been made in niche areas where tighter control of blasting is required.

Jan 1, 1997

By John W. Kopp

The U. S. Bureau of Mines investigated flyrock and burden movement from blasting at several limestone and basalt quarries in the upper midwest. Blasts have been studied at 14 different sites using high-speed cinematography. Blasting was accomplished in 75- and 150-mmdiameter holes using a variety of explosives. Films from each blast were analyzed to show burden velocities, observed flyrock distance, and direction of throw in relation to the shot layout. This technique, in some cases, allowed determining point of origin and cause of the flyrock as well as the flyrock range.

Jan 1, 1994

By Shulin Nie, Mats Olsson

The mechanism of rock fracture by explosive is a fundamental in rock blasting. It is generally believed that the shock waves from the detonation initiate the fractures. Then the detonation gases penetrate into the fractures and elongate them. However, our previous researches indicated that the detonation gases do not contribute significantly to the fracture propagation. In our latest experiment, blasts have been carried out in 8 large granite blocks. The main goal was to study the fracture mechanism, namely to determine whether the shock waves or the detonation gases fracture the rock.

Jan 1, 2001

By Calvin J. Konya

Many controversies and differences of opinion exist in blasting technology. The primer location in small diameter dynamite columns is an example of one of these controversial areas. It is generally agreed that in rotation firing of small diameter blastholes, primer placement near the bottom of the borehole is beneficial since it reduces the likelihood of cutoffs. The controversy results in the actual location of the primer in the bottom of the blasthole. Some references indicate that the primer cartridge should be the first cartridge in the bottom of the hole, with the cap pointed toward the collar of the hole. Others indicate that performance is improved with no sacrifice in safety by placing a tamped cartridge first in the hole, and the second cartridge being the primer. The following investigation provides some factual data for consideration.

Jan 1, 1980

By Ethan Steward, Kyle Perry

Underground coal mines have several dangers, one the most hazardous of which is the possibility of an explosion caused by the ignition of methane gas. To reduce ventilation costs, coal mines have the option to close off abandoned areas that are no longer active with structural seals to keep an explosion from propagating into working areas of the mine. These seals must be designed to withstand different pressure levels based on the potential of the atmosphere behind the seal to become explosive, either 50 psi (345 kPa) for inert atmospheres, 120 psi (827 kPa) for non-inert, and over 120 psi (827 kPa) for special cases. Though seals have been designed to resist the overpressure, none have been evaluated for their resistance to the impact of heavy objects. Underground explosions produce high velocity gasses that, traveling through mine openings, may propel objects in the mine at a high velocity causing them to impact and damage the mine seals. Seals damaged in this manner may no longer hold the pressure they were originally rated for and may fail during subsequent explosions or leak explosive gasses into active workings. To test the effects of impact on mine seals, a projectile generator and two seals have been constructed. The projectile generator is a 12-inch (30.5 cm) inner diameter steel pipe with a 4-inch (10 cm) wall, is 8.5 feet (2.6 m) in length, and sealed on one end. Projectiles are propelled by a charge of black powder with a wooden wad and are held in place by foam sabots in the bore. This system, combined with the large bore, allows firing of many different potential projectiles that may be found in an underground mine at a high velocity into the seals. The velocity of each projectile is measured by an infrared chronometer which can later be used to determine its impact energy. Impact effects on the seals are measured using strain gauges, LIDAR scans before and after impact, high speed cameras, and visual inspection. The focus of this paper is on the projectile generator design and initial testing.

By Travis Davidsavor, Stanley: Dong Vitton

Concrete is a common construction material used throughout the world, and with increasing demand of fast-track construction, blasting and concrete casting are occurring simultaneously at many sites where rock is being excavated for concrete placement. However, there has been significant disagreement in the construction industry as to what intensity of shock vibrations green, or fresh concrete can tolerate. Peak particle velocities are often arbitrarily chosen, or are simply based on materials such as plaster and drywall that have been more thoroughly studied in relation to damage. Previous research on green concrete has used the concrete’s static strength subjected to shockwaves at different ages as the primary damage criteria. In addition, the static strength tests have been based on curing time. However, changes in temperature or humidity can dramatically alter the hydration rate, which affects strength development of different cements. To account for temperature changes and humidity the concept of concrete maturity is commonly used and allows the researcher to see where the concrete was in terms of hydration progress. In general, static testing determines the failure stress that the concrete’s macrostructure can handle, and often failure occurs in the natural materials first or along large defects in casting techniques. Dynamic testing or high strain rate testing, on the other hand, loads materials at such a high rate that larger defects do not have time to react and instead the microstructure is more highly stressed leading to higher strength and stiffness values. This is known as the material’s strain rate sensitivity. Since dynamic testing better tests the microstructural strength, it is believed that it may provide a better way to assess damage to green concrete. Testing includes both static and dynamic compression as well as static and dynamic splitting tensile strength to assess whether damaged has occurred to the concrete. No significant statistical evidence was discovered that damage to the concrete occurred at five different “green” maturities from peak resultant velocities ranging from 10.66 in/s (271mm/s) to 4.40 in/s (112 mm/s) with average intensity of 6.7 in/s (170mm/s).

Jan 1, 2003

By Ery Wardhana, Fathur Rozaq, Jeff Averett, Nella Lubis, Carl Lager, Herry Saputra, Rudolf Sitorus, Relinda Sanistrya, Hormat Sinaga, Andhiko Maharjono

Efficient drill and blast operations are crucial for achieving optimal fragmentation, productivity, safety, and operational efficiency for the mining industry. However, conventional methods face significant challenges, including manual borehole marking and retrieval by survey teams, limited real-time data monitoring, excessive borehole collar deviation affecting blast quality, suboptimal drill productivity impacting person-hours and fuel usage, subjective judgment by drill operators on voids during drilling, and limitations in explosive charging design that do not match rock hardness. Rock hardness determination using lithological data from exploration models is often inaccurate due to the interpolation effect of wide drilling distances and depths, necessitating manual field verification using drill cuttings and historical blasting results. Furthermore, using single-density bulk emulsion throughout blast holes leads to suboptimal results due to varying rock properties. This study introduces an integrated approach that combines smart drilling technology with advanced emulsion technology to enhance drilling and blasting efficiency. The method utilizes smart drilling technology with GPS for precise borehole placement, Measure While Drilling (MWD) loggers, and real-time performance monitoring. Additionally, it integrates a smart Mobile Processing Unit (MPU) featuring a digital system and an automated gassing system (AGS). This setup allows for multiple emulsion densities within a single blast hole, customized to match the hardness index parameters determined from MWD data, addressing the challenges in drilling and blasting operations. The study evaluates the effectiveness of this innovative approach through comprehensive field trials and data analysis. While maintaining the digging rate according to production targets, key metrics such as drilling productivity, drilling accuracy, fuel consumption, powder factor, drilling and blasting cost, and fragmentation size were compared between conventional and new methods. Results showed a 56% increase in drilling accuracy, a 23% increase in penetration rate, a 19.6% increase in drilling productivity, and a 29% reduction in fuel consumption. This new method decreased the powder factor by 5.2%, impacting the drill & blast cost reduction by 2.3%. Moreover, fragmentation size improved by 12.8%, demonstrating the effectiveness of rock hardness-adjustable emulsion density in achieving better blast energy placement. In conclusion, integrating smart drilling and advanced emulsion technology significantly enhances drilling and blasting efficiency. This approach offers substantial cost savings and operational improvements, providing a strong rationale for adopting this innovative method in drilling and blasting activities.

Jan 21, 2025

By Allan King

Ammonium Nitrate (AN) is most commonly encountered as either a prilled solid or a highly concentrated aqueous solution, with or without organic ( e.g amine) nitrates. Under certain conditions of fire exposure involving prilled or solid AN, the molten state can be formed. The shock sensitivity of the molten material at temperatures greater than 220 Celsius has been found to be much higher than that of the prilled or solid form. Molten AN can be a precursor to events leading up to explosion of a bulk prill storage pile as a result of fire exposure. The explosion hazards presented by molten AN are a function of two factors; 1) its shock sensitivity and the deflagration to detonation ( DDT ) properties of the molten material, and: 2) the ability of large masses of unfueled prilled AN to be initiated and detonate. This paper presents the results of tests designed to determine the shock initiation and DDT properties of the solid ( prilled ) and molten AN.

Jan 1, 2008

By Alexander Hauck, Dimitri Jung, Uli Leiste

This paper describes results from small scale tests conducted to determine the distribution of impulse on target plates when subjected to loading due to the detonation of a buried mine. The tests were conducted with saturated sand, dry sand, and water as the loading media. Tests were conducted for flat plates and for plates with angled bottoms. Previous testing has shown that angled bottoms can reduce the total vertical impulse delivered to the vehicle significantly. Different stand off distances were investigated as well as loading of the targets both on center and off center. It is very important to know not only the total impulse delivered by a detonating charge but also how this impulse is distributed over the bottom of the vehicle. A complete understanding of specific impulse will permit those parts of the vehicle, taking the greatest amount of loading, to be sized properly. Experimental results were compared to analytical expressions provided by Westine and Tremblay.

Jan 1, 2010