Search Documents

By A. Lindo, M. Held

The formation of NOx fumes is an undesired occurrence and is dependent on a variety of variables. Methods for detection of such fumes with blast analysis tools are available using color schemes for grading, but no quantification tools to measure concentration and cloud totals exist today. In cooperation with DIRS (Digital Imaging and Remote Sensing Laboratory) at RIT in Rochester, NY, Austin Powder has been looking for methods and techniques to identify and quantify total amounts of NOx by capturing cloud activity via a video feed from a drone in combination with measuring NOx and subsequent cloud modeling (i.e., plume segmentation). To accurately measure fume events, Austin Powder and the RIT team have been collaborating in performing small scale blasts at an Austin test facility and then transferring knowledge learned to full scale blasts at customer sites. The collected data will allow to identify any relationships between the total amount of explosives used and the quantity of NOx produced. The analysis of the total amounts of NOx and identification of blast areas those fumes originate from will help to better understand key factors that contribute to their occurrence as well as to quantify the severity of such events. By quantifying the magnitude and concentration of fumes generated by non-ideal detonations, the blasting technique can be optimized to minimize unwanted environmental effects and improve public perception of blasting as a necessary component of societal progress

Jan 1, 2024

By R. Ranjan

Stanstead granite has been investigated with respect to its dynamic compressive strength and its strain-rate dependency. A standard Split-Hopkinson Pressure Bar (SHPB) apparatus has been employed to generate strain rates of up to ~500/s through high-velocity impact. The diameters of the test samples were 19 mm, and tested under impact velocities up to ~20m/s. It is found that even within this limited range of strain rates, the dynamic compressive strength for the granite showed nearly a 100% increase in value compared to those obtained under static loading conditions (e.g. compressive strength of 394 MPa at a strain-rate of 600/s, compared to 215 MPa obtained under static loading). The details of the test are described in terms of incident, reflected and transmitted stress pulses, along with means to achieve stress equilibrium in the test samples under dynamic loading conditions. The advantage and drawback of the use of ‘pulse shaping’ techniques to achieve dynamic stress equilibrium are also detailed.

Jan 1, 2010

By Gary B. Hemphill

Estimators will agree that estimating for excavation is the most difficult costing task. Equipment costs and production rates are the toughest to determine. The following illustration is a method that can be used for this determination.

Jan 1, 1976

By Barbara A. Sciever, John H. Sr Schue

Riverboat gambling has caused quite a sensation among people since its talk of coming to Illinois. The year 1992 marked the start of an era for people that had a penchant for gambling, it was the year that riverboat gambling was legalized in the State of Illinois.

Jan 1, 1995

By Magnus Gynnemo

The primary purposes of drilling and blasting in hard rocks is to fracture solid rock and prepare it for excavation and subsequent transport to the crushing plant. Using explosives in excavation operations without counting for the geology gives no consideration to the quality of the macadam product or the excess production of waste material (fines).

Jan 1, 1997

By Charles R. Welch, Charles E. Joachim

Underwater blasting causes not only ground shock but water-shock. Underwater shock attenuates less with range from the explosive source than ground shock and has the potential for killing fish or marine mammals or for damaging marine structures. The collapse and subsequent oscillation of the gas cavity surrounding the detonation can sometimes produce a greater impulse than the initial shock wave from the detonation. The airblast from underwater detonations can range from nuisance levels to damaging levels.

Jan 1, 1997

By Karl Ingmarsson

A model for drilling productivity and total drilling cost is presented. It specifically addresses down-thehole drilling, but also covers other drilling methods. The important factors are: 1, productivity in tons drilled; and 2, total cost per drill ton. For non-blasthole applications these factors are measured in drill feet and cost per foot. The model focuses on the entire system and allows the operator to optimize the system based on individual drilling conditions.

Jan 1, 1998

By B. M. P. Pingua & Md. Nabiullah

About 60 to 70 percent of bulk explosives are used in Indian coalmines to achieve coal production for power generation. Coal India Limited (CIL) is the major coal producing company in India. The average production of CIL is 400 to 450 million tonne coal per annum. The major subsidiaries of CIL are Northern Coalfields Ltd., Mahanadi Coalfields Ltd., Bharat Coking Coal Ltd., Eastern Coalfields Ltd, South Eastern Coalfields Ltd. and Western Coalfields Ltd. Most of the mines of CIL have watery holes. Therefore, high water resistance bulk explosives are preferred for better out puts.

Jan 1, 2008

By H. C. Verakis

This paper summarizes blasting accident data for over a quarter of a century (1978-2004) for all types of surface and underground mining operations in the United States. Although many billions of pounds of explosives and blasting agent have been used by the mining industry, the accident safety record has improved significantly in the past 25 years. Over the past decade, approximately 5 billion pounds of explosives and blasting agents were used annually in the United States. Coal mining has been and continues to be the dominant user of blasting agents.

Jan 1, 2006

By James G. Stuart

For precise control and timing of a blast, people use electric detonators. Most of these contain a fine metal “bridgewire,” that heats to the required burning temperature when electric current passes through it. Users should be careful. Stray voltage can fire these detonators. Some designs are particularly susceptible to electrostatic-discharge (ESD). We will discuss some of the accidents we have encountered in our forensic work. We will recommend specific safe procedures for handling and firing these devices.

Jan 1, 2005

By Alexander S. Escalante, Luis R. Ramirez, Nelson A. Arostegui

Research, analyze, discuss, design, and build an electric oven to perform one of the quality control tests the fanel or common fulminers to determine what temperatures they can detonate at. Give practical applications, conclusions, recommendations and bibliography.

Feb 1, 2020

By Grant Small, Deon Pieterse

Reactive ground conditions at an open pit manganese mine in the Northern Cape of South Africa resulted in an unexpected detonation.

Feb 1, 2020

By Earl C. Hutchison, Gene Smith

Extensive blasting was required to construct an underground tunnel for a 90 inch sewerage relief line. The tunnel and required excavation extended under an upper middle-class residential area in Atlanta, Georgia for more than a mile and a half and required the use of more than a half million pounds of explosives in the immediate vicinity of houses and residential apartments valued at more than 16 million dollars. Other houses and property valued at more than 80 million dollars were within range to claim blasting damages. An effective blasting damage control program was carried out which limited the number of blasting damage claims to less than 2-1/2% of the total number of potential claims. All but three of the small number of blasting damage claims which were made were effectively denied without any resulting legal actions and less than $3,800 was paid for settlement of the three claims.

Jan 1, 1981

By H Y. Fang, H Sutherland, R M. Koerner

Due to the increased number of complaints by property owners to blasting related industries an apparent need for a clearer understanding of blasting-related damage is needed. We feel that direct structural crack monitoring during such blasts is the appropriate measurement technique. Instrumentation and interpretation of results for taking such measurements are described in this paper. Typical results from blasting and other environmental effects are also described which can eventually be related to Fracture Mechanics principles in the hope of clarifying such disputes in an equitable manner.

Jan 1, 1976

By David R. Holberg

In the Kansas City metropolitan area, mineable Bethany Falls Limestone occurs 80 ft below river level under the 700 acre Park College Campus on the north bank of the Missouri River at Parkville. For 20 years prior to this project various firms passed over this opportunity to mine this property for construction aggregate because of uncertain costs, financial risk, and the difficulty of constructing an entry tunnel. This paper describes the drill and blast construction, rock bolting, and shotcrete lining of a 750 ft. long, 15% declining grade, truck tunnel through several Pennsylvanian limestones and shales.

Jan 1, 1997

BLASPA is the name for a computer code which can assist in the rapid optimisation of blasting procedures in an open-pit mine. BLASPA is based on a mathematical model of the blasting process, a model which has been developing since 1963 as a result of blasting research carried out at the College Militaire Royal de Saint-Jean under sponsorship of the Defence Research Board, and in co-operation with the mining and explosives industry. The model presently includes the following aspects: (1) Geometry, i.e. spacing, burden, bench height, collar, sub-grade drilling; (2) Explosives, i.e. types and grades of explosives, distribution into bottom and top load or decking, size of hole and coupling; (3) Hookup, i.e. parallel or angled firing, delays, location of primers. Computer costs are very small, by comparison with purely spherical AEC codes, so that any number of simulations can be carried out very efficiently. The system has already been used to carry out thousands of simulations for over 40 mines in Canada and abroad. It will be explained how such simulations become a useful guide for a mine's blasting engineer who wishes to optimize his blasting and drilling costs.

Jan 1, 1980

By Michael M. Jackson

"The mining industry has for some time compared explosive energy requirements to theresults obtained using ANFO. Drill patterns, powder factors, and explosive bulk strengthshave all been developed based on the detonation characteristics and blasting resultsexhibited by ANFO. However, there are some mining applications where the use of ANFOcan cause over_blasting if loaded to acceptable collar heights or surface breakage problemsif collar heights are reduced. A specialized, low strength, low density water gel explosivehas been developed that has loading densities in the range of 0.4 to 0.7 g/cc. The uniquecharacteristics of the low density water gel explosive is that the explosive can beformulated with a range of available bulk strengths while maintaining excellent detonationsensitivity for use in applications involving ore/waste control, restricted blast patterns,small bench heights, etc. The"

Jan 1, 1993

By Dale S. Preece

A discrete element computer program, DMC (Distinct Motion Code), has been used for several years to simulate blasting-induced rock motion. Recent enhancements of DMC's capabilities have included addition of an algorithm that couples together rock motion and gas flow. This allows the user to specify a particular explosive which also specifies equation-of-state and other parameters necessary to model explosive gas flow from the blastwell. Rock loading by the flowing gas is calculated automatically. The mechanism for calculating the rock loading is the subject of this paper. The rock motion effects the gas flow calculation by changing the porosity. DMC is currently being used on a SUN SPARCstation 2 computer workstation.

Jan 1, 1993

By C De La Cruz

The use of a thin-film piezoelectric stress gauge to determine the pressure profile in a detonating explosive has been demonstrated. These PVDF gauges have measured, in the borehole, the Chapman-Jouget pressure and the release adiabat of the detonation products for several explosives including ANFO and ANFO/emulsion mixtures. The technique can provide: (1) a direct measure of the blasting stimulus, (2) a sensitive QA tool for the blaster, and (3) a means to examine the magnitude and effects of preshock from adjacent bore holes. The PVDF pressure gauge is self powered, can measure pressure from a few bars to 400 kbars, has high time resolution (0.05 µsec), and is easy and economical to use.

Jan 1, 1997

By Geoff Baldwin, Alastair C. Torrance

The use of monitors to assess equipment performance is carried out on a routine basis in many industries. The benefits gained through process control in knowing exactly how the equipment is working far outweigh the initial capital costs of the monitor. In the mining industry several dragline monitors have been developed and installed on equipment through out the world, but to date none has been fully accepted by the industry. This paper describes the use of a sophisticated monitoring system which incorporates an onboard processor to assess both dragline and blast performance. The use of a radio telemetry link for data transfer has removed the need for manual data collection and transfer, leading to a more efficient and powerful system. Significant effort has been put into the development and verification of a dig index to allow blast performance to be objectively assessed.

Jan 1, 1990