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By James T. Ludwiczak

Drilling and blasting in a Karst (sinkholes and mud seams) environment has long been a problem for blasters, miners, quarry operators, contractors, and developers. While one cannot change the geological conditions, one can take some measures during the bidding process and the initial preparation of the blasting program to help reduce some of the problems. During the geotechnical investigation and developing the test/core drilling grid, the owner/developer needs to take some additional measures that will provide important data to the blaster to help reduce the problems associated with blasting this type of geology. The owner/developer must also understand that, due to the geologic conditions, the results of the blasting will not be ideal and there may be additional blast-related costs. If provided the proper geologic data, the blaster can develop drilling patterns and blast designs that will help reduce some of the more problematic areas.

Jan 1, 2005

By D. S. Preece, S. Silling, A. Bhuiyan, C. M. Lownds

GEM (Geologic Element Motion) is a Discrete Element Method (DEM) capability for blast-induced heave simulation with a very fast computational algorithm that can efficiently treat many different element shapes by utilizing alternating arcs and lines. GEM calculates rock motion from a knowledge of the gas pressure moving the elements. This requires an expression for the pressure vs volume, or the adiabat, of the explosion product gases. This work uses an analytical expression for the adiabat derived from the explosive’s properties. The effect of the explosive detonation pressure in crushing an annulus of rock, and setting up a shock wave, is termed Brisance. GEM incorporates a working hypothesis for the deleterious effect of Brisance on subsequent rock motion.

Jan 1, 2024

By Ian Bell

This paper investigates fragmentation in an aggregate quarry using the fragmentation-energy fan concept. Six blasts were monitored, located one behind the other in the same quarry area. The rock structure was blocky, the water level and the usage of explosives were variable within and between the blasts. The powder factor above grade was between 0.28 and 0.44 kg/m3 (0.47 and 0.74 lb/yd3). Fragmentation of the plant feed was measured using an online digital image analysis system and three belt scales. The oversize material that was not directly fed to the plant after the blast corresponds to 3‒9.3 % of the total. Data from image analysis was used to build the size distribution in the coarse range (fragments above 120 mm), and the passing fractions at 120 and 25 mm (4.72 and 0.98 in) obtained from belt scales data were used in the range 120‒25 mm (4.72 ‒ 0.98 in) . The non-dimensional percentile sizes between 10 and 90 % for each blast are described through power functions of the powder factor above grade; the model coefficients are statistically significant. From them, using the principles of the fragmentation-energy fan and the Swebrec distribution properties, the fragmentation can be expressed in terms of the powder factor by means of five parameters: the fan focus coordinates and the three parameters of a function of the exponents vs. the percentage passing. The model shows a good capability to describe fragmentation.

Jan 1, 2019

By Viktor Aranovich, Thomas E. Brown

The Almalyk Integrated Mining and Metallurgical Plant is located near Tashkant in Uzbekistan and is one of the former Soviet Union's largest copper producers. Almalyk consumes about 10,000 metric tonnes of explosives annually and expects this requirement to double by the end of the century as they implement a program to boost mine output.

Jan 1, 1998

By Paul Schmiesing, Matt Higgins

Central Oregon is a fast growing resort community centered in Bend, Oregon. Bend is bordered by the Cascade Mountains to the west and the high dessert to the east. Central Oregon is blanketed with lava rock with little topsoil. Ditch blasting is a staple in the area. Almost all utilities excavation (gas lines, sewer lines, water lines, and electrical lines) requires blasting. There is also a considerable amount of blasting required for site excavations and drywells. On average, there are over 500 blasts per year in Bend alone. All of this blasting is done using small holes, generally 2.5 inches in diameter. Typical ditches will have 200 holes, between 2-3 rows wide, with an average depth of 8 feet, and on 36 inch centers. Almost all shots are dry. Successful blasting requires careful control of drilling and loading. The vesicular basalt contains numerous lava tubes and caves making drilling and loading difficult. The rock conditions vary greatly from one side of town to the other requiring different powder factors and different scale of distances for vibration control. Caret%1 calculations of vibration predictions and use of site-specific seismic info is necessary. Marry shots will require deck loading and careful timing to ensure one-charge per delay. It is an every day occurrence to be blasting near residential and commercial structures or high pressure gas lines. Many times ditch blasting will incorporate excavation blasting. The different hole patterns used for the ditches and the excavation shots presents challenging timing sequences.

Jan 1, 2000

By Kenneth Eltschlager

The Surface Mining Control and Reclamation Act of 1977 requires that blasting be conducted so as to prevent injury to people and damage to public or private property. The three adverse effects are flyrock, ground vibrations and airblast. Blasting close to people frequently results in complaints of annoyance or damage. Federal and State personnel are responsible for evaluating the validity of the complaint. The elements to be evaluated include: reviewing blast logs, inspecting the mine, inspecting the house, measuring ground, air and structure vibrations, and predicting vibration levels. Computer spreadsheets, with their graphical capabilities, will be used to show how data can be cross tabulated to verify data accuracy. Complete statistical analyses of vibrations require more powerful software to make vibration predictions. Once all available data are gathered and verified, a decision on the complaint can be made.

Jan 1, 2001

By Norman Paley

A blasting project was undertaken at the Teck Alaska Red Dog Mine in 2005 to 2007 to determine the extent that using electronic detonators could increase Semi-Autogenous Grinding (SAG) mill throughput. The results of that project were reported at the 2010 ISEE Annual Conference. This paper is a postscript to that project and provides the fragmentation resulting from the implementation of a 15% pattern expansion using electronic detonators.

Jan 1, 2012

By Lynn Long

We have seen many new developments in the explosive and blasting accessory category, but one of the most useful items is the blast control plug. Blast control plugs are cone shaped units that are placed in the stemming just above the explosive load. They are placed about 8 to 12 inches up into the stemming material.

Jan 1, 1996

By D Linn Coursen

Detonation propagates in the subject blasting agent at about 2.7 km/sec when it is heavily primed but explosion propagates in it at only about 0.43 km/sec when it is lightly primed. When propagating at 0.43 km/sec, it produces a borehole pressure that is slightly less than 1 kb, but no yellow fumes or other sign of incomplete reaction. It is a pumped AN/emulsion blend to which additional water is added by circumferential injection at the inlet of the hose through which it is pumped.

Jan 1, 1994

By Kyle Apple

The following is a case study of how LuckStone Corporation improved their blast monitoring and documentation program. A number of resources already at their disposal have been utilized to improve the body of data collected from each blast. The tools being used include GPS, aerial photos, and a user-friendly push button format excel spreadsheet. The data collected include product by product records of materials used, distances to all concerned neighbors, seismograph data, etc: The spreadsheet has been designed to perform an ongoing analysis of blasting trends. The program has been carried out at a corporate level and is in use by blasters at each location. This paper addresses the advantages and drawbacks of this program. It also addresses the ways in which the various tools were integrated, Discussed as well is the need for simplicity when bringing “new” technology to the field and the steps taken in familiarizing the end user to changes.

Jan 1, 2001

By John Manka

Emulsion explosives consist of an aqueous oxidizer phase, a fuel phase, and an emulsifier. The ability to use lower-cost sources for any of these raw materials presents an obvious economic advantage to emulsion manufacturers. This paper focuses on using low cost waste drain oils as the fuel phase in emulsion explosive applications. Laboratory studies showed that emulsions made from waste drain oils and agricultural ammonium nitrate prills were usable for emulsion explosives though their shear stability was weak. Customer field results proved that waste crankcase drain oil could replace half of the virgin diesel fuel in emulsion explosives to make an effective emulsion explosive product with a very low cost.

Jan 1, 2003

By S. Nakamura, H. Taniguchi, K. Noguchi, H. Sugihara, T. Matsuzawa

It has been reported that expanded poIystyrene and ANFO prills ‘were mixed on a blasting site for controlled blasting (ISANOL). Although there seems to be few possibility of their segregation because mixing on a blasting site is done, there is a great possibility of segregation in packing, transportation and loading of the product due to the different densities of the two ingredients in Japan where mixing on a blasting site still remains inoperative. The fiee-flowing property of ANFO prills was lost with the passage of time because the Abel oil infiltrated into the expanded polystyrene and that gave the product high viscosity.

Jan 1, 2001

By John W. Brown

"Adequate dust control in and around rock drills is a problem that must be solvedfor the health and safety of workers running the drill as well as those working around thedrilling operation This paper will discuss the designs available from most drill manufacturers todayand the effort ‘nvolved in keeping them effective on a productive basis."

Jan 1, 1999

By S B. Richardson, D Mead, N T. Moxon

The use of air-decks to reduce explosive costs has become very topical in recent years. The majority of the research in this area has been arried out between the Soviet Union where reductions in explosive consumption of between 10-30% have been claimed with apparent benefits being gained in both fragmentation and movement. Work carried out by the University of Maryland using thick plexiglass blocks has supported these findings and indicated that air-decks in measetbe duration of action of the shock wave on the surrounding material by a factor of 2 to 5 (see Figure 1). Although the fracture network resulting from this mechanism is not as intense as that produced adjacent to the explosive charge it does appear to act over a larger volume of material. Although the mechanism attributed to air-decking has been studied in some detail the effect of this mechanism on the size distribution of material produced during a blast does not appear tot have attracted much attention.

Jan 1, 1991

By César Ugaz Castañeda, Paulo Fernández Alvarado, Richard Sotomayor Oblitas, Rocke Enríquez

Mina El toro has been making substantial changes in its operation to improve its social impact and productivity. Because of the use of gasified emulsions and electronic initiation system, it was possible to mitigate vibrations and carry out massive blasting, increasing its production by 4.2% and minimizing complaints from communities.

Feb 1, 2020

By R Yang, P D. Katsabanis, W F. Bawden

Understanding the mechanisms which are taking place during the propagation of a stress wave generated by an explosive charge is of high importance in the detection, characterization and prediction of blast induced damage to the rock. Vibrations caused by the detonation of an explosive are suspected to contribute significantly to the extension of the damage zone. Vibration monitoring close to a blasthole is a relatively new field of research, the hindrance being the scarcity of transducers capable of sustaining extreme accelerations without damage. This paper focuses on the vibration monitoring aspect of a blast induced damage study; the experiment took place at Queen's test site and was meant to record near-field vibration as close as 1 m from 100 mm diameter blastholes.

Jan 1, 1993

By R Vuolio, B A. Jonsson

In the center of Helsinki - capital of Finland - extensive blasting operations were carried out during the years 1982 - 84. At the corner of the streets Mannerheimintie and Simonkatu - in the Forum block - about 125,000 cu.m. of rock were blasted to give place for a new modern shopping centre (Fig. 1). Added to this amount of rock another 10,000 cu.m. were blasted for a transport tunnel to an adjacent underground bombshelter (Fig.2) which is to be used as a parking place in peace-time. The blasting work was demanding and difficult to carry out due to old buildings surrounding the work-site as well as computers and other sensitive equipment installed in some of them.

Jan 1, 1985

By Xu Tianrui, Jin Xiang, Pen Dianhua

Based on the results of research or investigation, this paper describes the causes of and countermeasures for unexpected accidents, such as premature, postponed or spontaneous explosions in blasting practices in China.

Jan 1, 1996

By Lizbeth A. Escobar, Phol M. Llanos, Maritza Y. Avila

The present research develops the estimation of critical parameters such as the distances and times between holes to avoid failure due to dynamic pressure in electronic detonators based on the near-field ground vibration model of Holmberg & Persson and the hydrodynamic model of Neyman.

Feb 1, 2020

By Jeff Hermanson

Every construction project has site specific problems that need to be dealt with. These problems may be created by the geology, location, weather, time constraints, etc. Once these problems have been solved their solution often can be transferred to other similar construction sites. The Crazy Horse Memorial project is no exception.

Jan 1, 1996