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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 Robert Hopler

A detonator is a copper tube about a quarter of an inch in diameter and an inch and a half long, closed at one end and containing in the closed end a small charge of fulminate of mercury, which has been found to be the best explosive for detonating dynamite. The fulminate charge is a very powerful explosive very sensitive to friction, lows or heat and very poisonous. When exploded it has an intense local action, shattering things in its immediate vicinity, but not extending very far away from the explosion. This kind of detonator is intended to be exploded by a spark from burning fuse.

Jan 1, 2014

By Cary Moffat, John Kita, Rick Walker

The Lac des Iles Mine, in an isolated area of NorthwesternOntario is a relatively new open pit platinum and palladium mine. They were encountering problems with the equipment and production scheduling when ramping down to begin production on the subsequent benches. A co-operative effort between Lac des Iles Mine operation people, ICI Explosives, and the mines drilling and blasting contractor - Consbec Inc., resulted in a decision being made to use full depth sinking cuts to provide access to the next bench.

Jan 1, 1996

By Robert Boehnke, Bernd Mueller

This contribution presents an innovative, statistically supported method to predict blast vibrations in rock mass. For modelling the processes during and after detonation, a theory is employed which is based on linear momentum (so-called momentum theory), strongly supported by new measurement methods. During the course of the investigations, the following parameters have been found to dominantly influence vibrations: ! charge WB, includes geometrical factors such as borehole length and diameter (kg) ! detonation velocity cd of the explosives used (m/s) ! distance r between the points of emission and immission (m) and the statistically determined negative exponent n ! factor RM or RS of the rock mass which is related to the specific blast momentum and the drilling and blasting technique used and is statistically determined together with the exponent m (mm/kg or mms/kgm)

Jan 1, 2004

By Frederick B. Kuhnow

Harmonic energetic delamination a building is being considered for demolition at a formerly known atomic power lab. The building is within a containment structure under a negative pressure, so that no radioactive material is leaked out to the environment. A new approach was developed to make this work possible.

Feb 1, 2020

By M. Araos

Non-ideal explosives can be characterised by different methods like velocity of detonation measurement, double pipe tests, underwater tests, aquarium tests, etc., to name a few. Both aquarium and velocity of detonation tests were selected to characterise a non-ideal explosive that is based on hydrogen peroxide, fuel, and void sensitisation. The detonation process in an aquarium of this sensitised explosive was captured at 80,000 frames per second using a high-speed camera. The explosive product was detonated using 51mm (2inches) diameter acrylic pipe charges. The product was detonated at different densities in an aquarium (cube box containing water). An aquarium provides a homogenous confinement for the detonation of explosives and more importantly, allows observing the shock wave as it changes the refraction index of water. The analysis of the video footage allowed the calculation of the velocity of detonation, pressure, gas rate release, and how the shock wave's shape in water changes with densities. It is suggested that the calculation of the rate of gas release could be related to the bubble data obtained from underwater tests.

Jan 1, 2024

By Yogesh Narula

Nevis Bluff Landslide - On September 17” 2000, a rockfall measuring lO,OOOm3 at Nevis Bluff, New Zealand, triggered a loday emergency. It ended when a hazardous column of rock that towered over State Highway 6 was finally shattered. The operation called for unusual and unique solutions using aerial bombing and inverted blasting techniques, not known to have been attempted before under these conditions, anywhere in the world.

Jan 1, 2002

By John Platt, Mark Stephens

"When blasting is required in critical areas and anticipated shot movement and quick cleanup areessential to the success of the project it is extremely important to use the best technology available to achieve the goals expected by the customer. Wampum Hardware was given such a challenge in 2014-2015 when the PA Turnpike and New Enterprise Stone and Lime hired the company to do presplit blasting along the PA Turnpike. The face height averaged 45 feet (13.72m) and the shots had to be controlled to stop within 60-75 feet (18.29-22.86m) of the face or in this situation before they entered the travel lanes on the PA turnpike. In many if not most blasting environments, it is essential in controlling the movement of a blast, to make certain that the face holes are drilled at exactly the right place, with the proper amount and type of burden in front of and to the sides of the borehole. Profiling is an important first step to insure that the holes are drilled at exactly the right place and showing us the correct amount of burden in front of each and every drill hole."

Jan 1, 2016

By Paulo Couceiro, Juan Navarro

The impact of rock blasting fragmentation and heave on digging performance in open-pit mining operations is usually the first true indicator of blasting outcomes. Within the typical excavation cycle, the bucket loading time or instantaneous digging rate are the ones that present the strongest correlation with rock fragmentation size distribution, swelling, and shape of the muckpile, a part of rock mass hardness, equipment size, power, and others. As the efficiency of unit operations becomes increasingly important for long-term mining strategies, cost-effective approaches are needed to increase mine productivity. In this line, the performance of downstream operations, such as digging, hauling, and comminution, may be affected by the energy input in blasting. This requires a better understanding of the explosive’s energy role in such unit operations in order to drive consistent improvements. Therefore, this paper examines the impact of the explosive’s energy distribution on shovel diggability from production shots carried out with different explosives in an open pit gold mine, with the aim of modelling the interface between blasting and excavation.

Jan 21, 2025

By Ron Gilbert

Every day, demand increases with over all population; supply must follow. People must have more food, shelter, and mobility. Raw materials must be mined. Roads, trenches and foundations support the quality of life.

Jan 1, 1996

By W. J. Birch, R. Farnfield, S. Hosein, C. Johnson

Modern smart phones include accelerometers based on MEMS (Micro Electro Mechanical System) technology giving the possibility to measure both acceleration and orientation. The widespread use of such phones has driven technological development to such a degree that it is now possible to obtain a triaxial accelerometer unit, that also include signal conditioning and analogue to digital conversion, in a package smaller than 1 cm2 (1/2 sq.in) for a relatively low cost.

Feb 6, 2023

By Guillermo Lazcano Ríos, Jorge Parvez Aguirre, Alejandro G. Díaz Berríos, Felipe Rodriguez Alveal

Codelco's Chuquicamata Underground Division (DCHS) faces issues due to collapses in its subsidence streets, which hinders the advancement of the subsidence front and leads to the loss of areas and reserves. To address these issues, DCHS and Orica have developed a new excavation methodology based on pre-loading explosives in high drawbell. This methodology involves creating a high drawbell extending from the floor of the production level to the ceiling of the subsidence level, divided into two phases: upper and lower. A resin stemming is used to separate these phases. The excavation strategy adjusts to variables such as reception volume, fluffing, and excavation geometry, involving vertical pre-loading of the explosive and the use of a separating element between the phases. The test aims to validate the new excavation methodology and the retaining element in the rock mass, evaluating aspects such as drawbell geometry, impact on the rock mass, damage to the retaining element, and fragmentation. Wireless electronic detonators are used in the upper phase to improve safety by eliminating the need for physical connections, while traditional electronic detonators are employed in the lower phase. Low-density bulk emulsion is applied to minimize the impact on the Crown pillar and extraction point, and higher-density explosives are used above the subsidence level to ensure good caving. Results showed that the blast achieved 86% conformity with the theoretical design. Resin stemming allowed for 100% effective detonation in the upper columns, and the fragmentation obtained was 5.44 inches, which was less than expected. No damage to the Crown pillar was observed, and the explosive quality met standards. This technique has proven to be effective and viable, suggesting the possibility of eliminating the subsidence level in future levels, resulting in savings, and providing greater stability to the rock mass.

Jan 21, 2025

By Wm. Reisz

There is no universal standard for Standard Operating Procedures (SOP’s). Every blasting operation has its own unique circumstances, its own methodologies and its own unique demands. It would be nearly impossible to create a one-size-fits-all document that would be totally appropriate for every blasting scenario. But there are universal objectives that should be adopted in any set of blasting SOP’s.

Jan 1, 2010

By Harry L. Siebert

Pre-splitting was substituted for line drilling to achieve stable rock slopes and reduce excavation beyond the pay line on a Connecticut highway project in 1962-63. Changes have occurred in developing rock slopes that were not foreseen by Alan Bauer and Jim Scott who in the early days understood the relationship of explosive energy to stable slopes. Cushion blasting as currently used produces slopes designed to blend or complement the natural landscape with slope holes detonated after the main body of holes. Pre-splitting is the opposite. The best results have been achieved by detonating the pre-split line of the holes first to allow readjustment of the slope plane fracture and a separate blast for the main body of loaded holes.

Jan 1, 1998

By Greg Shapiro, Paul Dr. Worsey

Mining, quarry, and construction blasts are becoming more and more dependent on bench profiling. The use of accurate profiling gives the blaster better data for the most efficient blast results. So, we ask the question: What is the best method for measuring and analyzing burden?

Jan 1, 2019

By Frank Sames, Brad Terhune

In many construction projects and in most quarrying operations drilling and blasting remains the only feasible method of loosening rock in the removal of rock or overburden, the development of the quarry and in the production process of crushed stone. Often, a blasting plan is required for the project or the quarry’s permit with primary concerns over safety and site security, and compliance with environmental regulations or standards. From this plan, a blasting program has to be developed considering the varying requirements of production, the advance of the mineral extraction and the environmental impact. The actual blast design requires a planning and optimization process. This optimization process is driven by the blasting technicians/engineers, project or mine management and often by community concerns. The blast design process comprises the selection of blast parameters, including the explosives, and the actual layout of the blast. Design tools and controls range from conventional methods based on established blasting practices to advanced design tools or computer models. Blast monitoring and evaluation can also range from empirical to advanced blast assessment. The data and information from each blast or a series of blasts can further be used in the optimization process. Its success depends upon recording the data, the timely transformation of the data to relevant information, and the development of process oriented knowledge. The elements of the blast design process are summarized and described with examples of state-of-the art engineering controls. The reporting and monitoring of individual blasts is discussed with respect to data management and information systems. A conceptual overview of the components and interfaces of a blasting program is given and discussed on the background of technical, management and community concerns.

Jan 1, 2004

By Jorge Blázquez, Pablo Ravanal, Paulo Couceiro, Juan Navarro

Blasting performance is influenced by rock mass properties and blast design parameters. From them, the rock is the only variable that cannot be modified, but it can be measured, so that, blast design variables can be adapted to optimize the results. A new methodology to assess rock mass quality from drill-monitoring data from both autonomous and manual rotary drilling modes is described to guide blasting in open pit operations. For that, a thorough normalization process has been developed to minimize external influences induced in the data by the rig system for autonomous mode and by the operator intervention for manual mode. Principal component analysis has been used to combine MWD information. Two rock description indexes are derived directly from Measurement While Drilling (MWD) data collected. The first index is a Structural factor that classifies the rock mass condition in three classes (massive, fractured and heavily fractured). The second index is a Strength factor that classifies the rock according to the strength properties. Both indexes have been combined to obtain an overall drilling rock factor along the hole. This has been named by the authors as the X-Rock model.

Feb 6, 2023

By David Cheung, S. Paul Singh

"The characteristics of a blasted muck pile can have a significant effect on the productivity and economyof loading and hauling operations. Poorly fragmented and tight muck piles, caused by insufficientdisplacement of the broken rock, lead to higher digging and hauling costs. Therefore muck pile must be tailored to suit the loading and hauling equipment. In order to achieve this objective, it is imperative to understand the relevant muck pile characteristics and factors governing them. In general, muck pile characteristics are governed by the blast design parameters, rock mass geology, explosive characteristics and post-blasting requirements."

Jan 1, 2017

By Romel Villanueva L.

"Peru does not produce ammonium nitrate; nevertheless it is a large consumer of both, porous prill (PP) and high-density (HD) varieties. Explosives cost is an important preoccupation in Peru, due tofluctuations of the imported ANFO grade Ammonium Nitrate (AN). The use of Gasified Emulsion (GE)-manufactured with much cheaper HDAN- has become an alternative to reduce such costs. However, some problems were reported in the application of pure GE, including explosive percolation in highly fractured rock and lack of sensitivity by the effect of hydrostatic pressure in very deep holes. It was, hence, proposed to have an explosive based on GE too, but more robust and capable to keep the shape of the explosive column into the blast hole, by minimizing the leakage into the cracks. This could be achieved by adding limited amounts of lower priced HDAN, at the same time of providing gas pressure benefits. Other alternative is to add a low-density material, such as polystyrene prills, into the GE, although it reduces the explosive energy. The chemical gassing controls the density of GE, thus it can be obtained a wide range of densities."

Jan 1, 2016

By K Taylor

Small scale tests have been conducted in blasting vessels in the laboratory, where the effects of explosive composition, charge diameter, explosive confinement as well as additives to the explosive were examined on NO, NO2, CO and CO2 production. Fumes were analyzed continuously using a flue analyzer, providing analysis every 15 seconds. The results were compared to previous work conducted in the laboratory and to literature findings. It was found that the type of the explosive was the most dominant factor with emulsion explosives producing significantly less amounts of toxic gases. ANFO was shown to always produce nitrogen oxides, even when fuel rich. Tests were also conducted by detonating explosives in broken rock, simulating the release of products of detonation during the formation of a muckpile. Products of detonation were affected by the presence of atmospheric air or rock around the charge. Gaseous products of detonation migrated through the rock piles at different rates, resulting in a change of toxicity values over time. In the small scale experiments, CO appeared to travel faster than CO2 while NOX was not identified. Analysis of the gases that were released during digging, several hours after the blast, resulted in high temporary concentrations of toxic fumes.

Jan 1, 2014