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By Clara Godoy, Álvaro Dapía, Paulo Couceiro, Pablo Segarra, José Ángel Sanchidrián, Juan Navarro

This paper applies geostatistical tools in Measure While Drilling (MWD) data to estimate the probability distribution of values in all the points of the studied domain in order to assess the continuity of rock classes between boreholes. The analyses carried out by Ghosh et al. (2018) and Navarro et al. (2019) have been used as starting point of this work to classify the geotechnical rock condition in four classes: solid rock, fractured rock, cave- in rock and cavity. From it, an application for the geotechnical rock condition of orebodies have been developed, aiming at characterizing the rock before the charging the holes to minimize unexpected rock conditions and to address issues associated with charging and blasting operations. Such problems are closely related with non-optimal rock fragmentation after blasting.

Feb 1, 2020

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 Aris Tambunan, Nella Lubis, Nurafrianti Saala, Komang Widhiayanto, Herry Saputra, Rudolf Sitorus

Maximizing mining recovery rates and minimizing ore loss are pivotal objectives for economic efficiency and operational effectiveness. This study explores methods to address these imperatives by enhancing ore production and recovery through improved blasting techniques and spillage control in the Martabe Gold Mine Project in North Sumatra Province, Indonesia. Between 2018 and 2021, the average mining recovery rate stood at 93%, resulting in a potential annual ore loss of 7% and a potential quarterly financial impact of close to $2 million. Maintaining and enhancing mining recovery became crucial, with a planned 30% increase in total material movement for 2022. The mining recovery target for 2022 was set at 96% based on best achievement historical data from 2021 to increase ore tonnage by 203 KTon per annum. To achieve the primary objective of increasing ore production by improving mining recovery, the study focused on predicting and controlling the movement of blasted ore to reduce spillage and enhancing the grade control model to reflect actual conditions post-blasting. Several alternative solutions were explored, primarily emphasizing drilling and blasting activities. Essential methods included capturing the actual blasting movement to adjust the ore block based on blasting design data and post-blasting muckpile topography. This approach minimizes ore loss by providing output as ore block adjustment based on post-blast movement data. In addition, the tie-up design was adjusted to control ore spillage outside the pit ridge. The implementation of these methods yielded significant improvements. Adjusting the ore block based on actual blasting movement contributed $1,545,764 in benefits. Controlling ore spillage outside the pit ridge achieved a 10% reduction in spillage, contributing $79,184 in benefits. These enhancements successfully met the 2022 mining recovery target of 96%, marking a 3% increase from 2021. Consequently, ore loss was reduced by 178 KTon throughout 2022, resulting in a financial impact of $7.3 million. The study underscores the significance of precise blasting techniques and effective spillage control in enhancing mining recovery rates.

Jan 21, 2025

By Matthew Clay, Colin Chambers, Susan Hookham

Opencast (quarries) and underground mines around the world use blasting methods to mine valuable ore. Traditional blasting systems use technologies such as electric delay detonator systems (developed in the 1950s) and non-electric detonator systems (developed in the 1970s) to initiate a detonation train to blast rock more effectively, and so retrieve valuable product more efficiently. However, the lack of precise control over blast timings with these approaches can result in undesirable outcomes such as significant flyrock, excessive ground vibration, uneven grade of rock and misfires (in which sections of the blast can remain unfired). The development of Electronic Initiation Systems (EIS), first used in the 1990s, introduced a higher level of control over the blast. These systems greatly reduce the negative issues associated with blasting. However, this precision introduces complexity, and with this complexity comes difficulty in demonstrating the predictability, safety and reliability of such systems.

Jan 1, 2017

By Joshua Hoffman, Philip Mulligan, Braden Lusk, Tristan Worsey

Blasters rely upon detonators to achieve the designed timing sequence to move material where it needs to go, minimize vibration, or optimize fragmentation. At times detonator inventory on seldom used delays may be slow moving. This can lead to detonators being used long after they were manufactured. This paper addresses the potential shelf life concern as it relates to timing accuracy of shock tube detonators. A recent study was conducted to study the timing accuracy of non electric shock tube detonator systems. A follow up study was then conducted to determine the degradation of the non electric shock tube systems accuracy with time. The follow up study is presented in this paper. Samples of detonators from the initial study were set aside for approximately one year and then tested. The results from the aged detonators were compared to those of the detonators that were tested in the original study. As an extreme case a third set of shock tube detonators was tested using detonators that were between eight and nine years old. The results from these tests are presented as well. Each system was tested at a short medium and long delay time. Statistical analysis was conducted to determine the effect of time on the detonators accuracy. This paper quantifies the importance of regular inventory cycling to help preserve manufactured timing when using non electric shock tube detonator systems.

Jan 1, 2013

By Winfried Rosenstock, Hans-Jochen Blatte

"The guidelines of fire-fighting strategies have to be rewritten, latest since theYellowstone-Fire.CF- and S3- procedure are developed to achieve firelines of 500 ms/ h length and 100 mswidth per unit. Thereby two stretched charges burried in different depth and fired delayedin one round covering 50,000 ms2/ h with non-combustible, natural material (soil) at oncein seconds."

Jan 1, 1993

By Tom C. Palangio

Commercially available online particle size analyzers (OPSA) are in their third decade of development (Palangio, T.C., 1985), (Franklin, J. A., Maerz, N.H., 1987), (Maerz, N.H., Franklin, J.A., and Coursen, D.L., 1987). The installed base of operating analyzer numbers is in the hundreds. This paper takes a look at five critically important relationships that users have discovered through the use of OPSA systems. The two key attributes of these systems are: 1) consistency and, 2) historical context compared with traditional practices.

Jan 1, 2016

By Corry Goumans

Description of Project: Drilling, Blasting and Installation of Catenary Cables. Project Owner: Rio Tinto Alcan

Jan 1, 2010

By Zong-Xian Zhang

In sublevel caving mines, serious eyebrow break usually gives rise to lower ore recovery, higher dilution, and worse safety for the people working in the field. For example, chargers must go near the caving region and stand under the damaged eyebrow where a hanging stone may suddenly fall down or rock fragments may quickly roll down.

Jan 1, 2011

By Michael Milstein

Northwest Research Station said as more and more older dams are removed to benefit fish, it’s become clearer that rivers rework themselves quickly.“Where the dam is relatively small, it’s a quick response,” he said. “The river quickly forgets.”

Jan 1, 2010

By Tom Snyder, John Brulia

"The U. S. commercial explosives industry annually transports thousands of tons of hazardous materials (HM) in the form of explosives, oxidizers, and combustible liquids by highway in truck-tractor/trailer combinations and straight trucks, including pickups. Managing risk during transportation is every commercial explosives industry motor carrier’s number one job."

Jan 1, 2014

By Joseph Kennedy

How do terrorists and other criminal bombers acquire explosives to be used in an attack against U.S property and/or citizens? The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) with nearly 40 years of investigating bombings and other explosives incidents, has learned that explosive materials intended to be used in criminal acts are obtained primarily by theft, clandestine manufacture or diversion.

Jan 1, 2010

By R. Ticona, J. Alarcon

In the continuous search to provide comprehensive solutions and identify opportunities to improve ore traceability, from the blastholes to mill feed, different ore traceability systems have been developed, which allow tracking the ore and associating its geometallurgical characterization of different sectors of interest from blasting to the processing plant, facilitating decision making and operational actions when detected during each stage of the plant. With the objective of improving the ore tracking from the mine to the processing plant in a Peruvian copper mine operation, the impact on the processing plant was evaluated in relation to blasting optimizations through a tracker system, relating the processes performance of the whole production chain with the geotechnical and geometallurgical properties ores in real time in the process plant: detecting when it was feed waste, high grade ore, low grade ore and ore with arsenic, among others. Unit and integral tests were carried out over a period of three months, with an implementation of tracker detection portals in the processing plant, which allowed to verify the proper communication of data and the web platform. The tests were focused on several blasts where the ore was in contact with waste and it were directly sent to the plant, with a classification by type of grade (high, medium, and low grade), type of material (ore-waste contour), this stage allowed to make operational adjustments in the field and in the mining operation. Finally, in the economic results, the special tests had 1000 trackers, obtaining for this project a sensitization of a cost benefit for the test stage, for the reduction of 50% of the waste material feed has crushed, with an estimated benefit of 1,987,646 USD.

Jan 1, 2024

By Tapan Goswami, Brent Geoff

Mining multiple steeply sloping coal seams introduces challenges in terms of safety and productivity. Work on steeply sloping surfaces for the processes of bench preparation, mark-out, drilling, loading and blast tie-up, coal cleaning and recovery is inherently hazardous. Furthermore, a large number of mining cycles is usually necessary, as small rounds are required and each layer is separately drilled, loaded, blasted and excavated. This exposes personnel and machines to additional risks and also incurs higher unit costs of mining as machine productivity is reduced. A case study is presented of a mine in New South Wales, Australia where three coal seams are separated by layers of inter-burden rock. Due to the unfavourable sloping nature of the coal seams the conventional practice was to drill and blast each layer separately.

Jan 1, 2010

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 Tony Rorke, Tamara Wiseman

Due to the advancements in technology it becomes easier to obtain accurate measurements for mining, quarry, and construction operations even in the most remote places. The use of off-the-shelf photogrammetric imaging technology and unmanned aerial vehicles (UAVs) are becoming more common in the mining industry for blast design and surveying. Pattern optimization, face profiles, pre and post blast volumetric, stockpile measurements and mine mapping are all areas where these technologies can be used with ease.

Jan 1, 2015

By John Wall

The use of electronic detonators in civil tunnelling applications, to reduce vibration is small firings has been successfully utilised for a number of years. As part of the mining industry’s commitment to reducing blast damage during the development cycle in underground mining applications, a series of development blasts using eDevTM electronic detonators in typical mining applications was conducted in North Queensland, Australia.

Jan 1, 2012

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 Chick Kerkering, Stephen Iverson

Perimeter control blasting is common in civil construction projects but not as common in mining. A poorly designed and executed underground mine development blast design can result in unwanted wall rock damage. This damage increases the risk of rock falls and injury. With the availability of good drilling equipment, it is a simple matter to add the few extra holes needed to change conventional drifting into drifting with perimeter control.

Jan 1, 2008

By William C. Pearson

In past years, the usual justification for underground mining of limestone has been the depth of the overburden, perhaps 100 feet thick or more. At our Okolona Quarry in suburban Louisville, Kentucky, the overburden is usually shallow -- it averages 8 to 10 feet in thickness. However, in July 1980, we began development of an underground limestone mine on that property which also includes surface mining operations.

Jan 1, 1983