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By Cathy Aimone-Martin, Frank Achuff

The New Mexico Department of Transportation (NMDOT) and the Federal Highway Administration (FHWA) have let a contract to Sierra Blanca Constructors for a design / build contract along 38 miles US 70 in Lincoln County, New Mexico. The project will improve safety of travel along the corridor and facilitate the adopted economic development goals of the state. Proposed improvements include widening the existing highway from two lanes to four lanes, providing left turn lane options at selected locations, improving access for businesses and residences, aesthetically enhancing retaining walls, improving storm drainage and replacing the existing pavement with a 30 year mechanistic imperialistic perpetual pavement design. The US 70 Hondo Valley highway project is situated in a narrow valley with steep limestone walls, passes along a Scenic Byway and numerous historic ranching communities with structures that date back three centuries. The scope of work included requirements to monitor and mitigate blasting, noise, and vibrations. The contract was very presumptive with regard to blasting design and procedures. These included visual impact mitigation to treat and stabilize slope cuts, the Migratory Bird Treaty Act protecting roosting and nesting birds from airblast, and the protection of historic and cultural features such as acequias, wells, and structures. Public involvement affecting the rock blasting design has come from citizen task forces and committees concerned with highwall aesthetics and preserving the scenic byway and cultural resources. Constraints placed on the blasting program from agencies and the communities are often at odds. For instance, blasting must produce stable yet natural-looking walls to preserve aesthetics. Restrictions have been placed on pre-splitting and smooth-wall blasting yet safe slope are of the highest priority. This paper presents details of the design/build process undertaken by the contractors to conduct blast rock in an environmentally sensitive region. Blast designs consistent with good construction practices and used to comply with the many federal and state highway stipulations are described.

Jan 1, 2004

By Felipe França Sitonio

Parameter’s control of explosives used in blasting operations have become more relevant over the years, bringing a better understanding of detonation performance. Giving into consideration that bulk emulsion density’s variation reflects directly on blasting results due to its importance in product sensitivity and velocity of detonation (VOD), blast designs are conducted assuming that cup density measurements are reliable and explosives gassing agents will perform as per specifications. Nevertheless, confinement conditions in boreholes like temperature, presence of water and surrounding circumstances of rock mass are often neglected on predictive modelling and off-site measurements. This paper describes the assembly of a device equipped with pressure sensors and its utilization in confined boreholes of an open pit mining operation, aiming to obtain in situ monitoring of density variation in several explosive columns. After we developed a software to get and process data of a hardware prototype and the device functionality was validated in water, oil and quarry mining experimental trials, 7 of 291 boreholes in a gold mine operation were chosen to be monitored with two probes each, placed at the top and at the bottom of the explosive column profile. The results obtained enabled a comparison between the bulk emulsion density variation when acting in different environments, since we selected boreholes with diameter of 101.6 mm (4 in) and 139.7 mm (5.5 in) and some with presence of water. Besides the increase of explosive density with depth related to hydrostatic pressure increase, we found an overall error of 6% in cup density measurements when compared with sensors placed at the bottom of boreholes and 2% when compared with sensors placed at the top of explosive column. These findings provide detailed insights into how bulk emulsion explosives behave in different circumstances including depth and borehole diameter, giving the opportunity to re-evaluate blast design parameters such as its geometry, sequence pattern, charging profile and explosive composition.

Feb 2, 2020

By A. Ribeiro

The effective utilization of resources and process optimization play a crucial role in the sustaining and growth of overall businesses. This principle holds true in the mining sector, where particular attention is required during the comminution steps. This necessity arises from the fact that mining operations often consume substantial amounts of energy in mineral processing. Therefore, it becomes imperative to thoroughly study the integration of comminution steps. In many instances, an approach to be studied is the operation commencing with the drill and blast phase and culminating in the grinding product process. Nevertheless, establishing an optimal integration between drill and blast operations and the grinding phase is a complex undertaking due to the direct influence of rock characteristics on this process. And in many cases, the complexity and variability of such physical characteristics makes mining operations to ignore such influence. Consequently, Enaex Mining Technical Solutions (EMTS), in collaboration with Lundin Mining's Chapada Mine engineering team, and with the assistance of Hatch Consulting and Technology, has undertaken a comprehensive study aimed at enhancing mill throughput at the Chapada operation. The basis of this study lies in characterizing the rock masses present in the Chapada Mine to gain a deep understanding of the material that needs to be comminuted. Subsequently, the mineral processing team determined the most suitable size distribution for the Run-of-Mine (ROM) material. With this information, the drilling and blasting team built a site-specific blast fragmentation model, able to simulate various blast design scenarios. This approach enabled to optimize the utilization of available drilling and blasting resources while striving to achieve the optimum ROM characteristics. Since 2021, the Mine to Mill methodology has been progressively implemented at the Chapada Mine. As a result, the blasting engineering team now utilizes the blast plans generated by the fragmentation model simulations as a foundation for designing blast plans that align with the operational and financial capacities of the mine. Overall, it was predicted that this implementation could lead to an average increase in mill throughput of 13-22 % depending on blend feed, once all recommendations are implemented. Even with partial implementation, plant results demonstrate a 5 % increase compared to the period before the Mineto-Mill project, without any coarsening of the associated grinding product size.

Jan 1, 2024

By M. K. Ameen, R. El-Hacha

This paper presents the analytical results obtained from numerical simulation of reinforced concrete slabs strengthened with various FRP systems and subjected to blast loading. A three-dimensional finite element model using AUTODYN software was used to predict the overall behavior of the slabs. The numerical results were validated by comparing with experimental results from a program carried out to investigate the efficiency of different strengthening systems on the blast resistance improvement of small-scale reinforced concrete (RC) slabs. The experimental program consisted of testing nine RC slabs strengthened with three different externally bonded (EB) FRP systems attached at the bottom side of the slabs and one RC slab tested without strengthening for comparison purposes. The EB FRP strengthening systems investigated included two layers of Carbon Fiber Reinforced Polymer (CFRP) sheets, two layers of Glass Fiber Reinforced Polymer (GFRP) sheets, and one layer of Glass-Fiber Resin Polymer (GRP) sheet. Different epoxy resin, patching mortars and impregnating epoxy adhesives were used for the slab surface preparation and FRP system application of the strengthening layers. The aim was to evaluate the residual strength of the test specimens after exposure to blast loads. The blast loading parameters were evaluated for each test using AUTODYN simulation and compared with the computer program CONWEP. All specimens were subjected to same spherical TNT charge weight and stand-off distance with the respect to the slab top surface. Extensive comparison is made between the experimental results and the AUTODYN simulations for the control unstrengthened slab and the strengthened slabs including time history records of the bottom steel strain and mid-span acceleration and the peak dynamic deflection of the slabs.

Jan 1, 2010

By Alan R. Gadberry

To resolve drilling and blasting problems, rather than treating symptoms and allowing problems to grow, the mine operator needs to change the way he operates. When a mine operator discovers a drilling and blasting result that he doesn't like, it is easy for him to think of that disappointing result as a problem. More often than not, however, that result is only a symptom of a problem, and the real, underlying problem cause can be seen when the operator looks in the mirror. Symptoms and problems relating to drilling and blasting are resolved when the mine operator makes appropriate changes in the way he manages his operations.

Jan 1, 1985

By Mick Lownds, Ruilin Yang

The potential advantages of electronic detonators with accurate timing have been increasingly recognized by the blasting community. However, in comparative blasts the results with pyrotechnic timing are sometimes comparable to those from electronic timing. Statistical variation in blast results is a plausible cause of these observations.

Jan 1, 2011

By Richard Givens, Thomas Baginski

Technological advancements in warhead designs and implementations have driven the development of arrayed initiation networks of highly accurate, highly reliable, and extremely safe detonators. Recent development efforts have produced advanced Exploding Foil Initiator (EFI) based systems that have been adapted for civilian use in commercial blasting applications.1,2,3,4,5 This novel, high technology system promises multiple improvements and advantages over the manufacturing, transportation, tracking, storage, inventory and field operation of current detonator systems. Ultimately the insertion of this technology would result in fielding a Non-Energetics Based Detonator (NEBD). Insertion of complementary technologies into the detonator’s supporting systems would greatly advance current detonator hardware/software.

Jan 1, 2011

By Steve Dillingham

The origin of the written blasting log or shot report can likely be traced back to the earliest annals of blasting and record keeping. These records were, for the most part, a way of checking inventory, production progress, or billing, and not necessarily designed with the intention of being used as a legal document in a court of law. As our litigious society has evolved to include far reaching regulatory requirements, however, the blasting log has developed to support and aid in the defense of the common blaster from blasting lawsuits by providing a comprehensive written report of his or her actions.

Jan 1, 2002

By John Petty, John Loviza

As a blaster, have you ever had that uneasy feeing in the pit of your stomach as a codes enforcement official drives onto your jobsite? Have you ever needed an ally in a court of law against an unjust damage claim? Have you ever wished for a better and more open relationship with the guys who wear the badges?

Jan 1, 1996

By Thomas Pallua, William C. Gates

"Two major railroad companies have identified several segments along the railroad corridor betweenTehachapi and Bakersfield, Kern County in California that require construction of a second track to improve operations in this area. The total project proposes an upgrade of five segments along the Tehachapi-Bakersfield route. The authors focused on two segments: Walong to Marcel and Cliff Siding Extension. The second track project comprised design of a through-cut adjacent to an existing tunnel and up to 120-feet-high (36m) side-hill cuts (both in granitic rock). The authors characterized the geologic ground conditions and ground behavior, including rock mass quality and strength using a combination of rock core drilling and rock slope mapping. The rock mass is generally characterized as granitic tonalite with strong core stones surrounded by a matrix of decomposed granite (DG)."

Jan 1, 2017

By T Barnes, K D. Sexton, T J. Tope

For the past decade, the U.S. Department of Defense (DoD) has been under increasing pressure from state and federal regulatory authorities to develop management strategies for waste streams generated at its bases, installations, and ranges. Since passage of the Federal Facilities Compliance Act (FFCA) in 1992, concerns have focused in particular on military munitions and energetic waste streams.

Jan 1, 1997

By Patrick D. McLaughlin, C Fordham

"The project outlined in the accompanying paper was to densify beach sands on the pond side ofa tailings dyke to the strength required for future dyke construction, This was to be achievedthrough the detonation of relatively small explosive charges in the sand to cause settlement intoa denser state."

Jan 1, 1992

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 Douglas R. Burns

In New England, an area of the country where 3 ½" holes are considered large diameter,we are starting to experiment with 5" and 6" holes. The results are excellent in some areas and poor in others. The geology of rock is the major consideration to account for the blasting results.

Jan 1, 1997

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 Tapan Goswami, Stephen Jeric, Geoff Brent

Highwall failures in large deep open cut mines have very significant safety and commercial implications. There are many factors influencing the stability of highwalls. The major influence is the interaction of the local geology with the shape of the pit wall. This factor is in the realm of the geotechnical engineer and is beyond the control of the blasting engineer. However, a secondary influence is the blastinduced damage to the wall. In most open cut metal mines the blasting strategy to control this damage involves the use of separate production and trim blasts bounded by presplits at the final wall.

Jan 1, 2011

By Stephen Mansfield, Nathan West, El Khalil Seyed

In October 2017, a multi-bench failure occurred in the east wall of the Guelb Moghrein copper and gold mine in Mauritania. The failure extended 100 m (328 ft) vertically and horizontally and resulted in the sterilisation of ore, but no equipment or personnel were put in danger. The remediation plan successfully removed the failed material and the cutback resumed to a modified pit design, leaving ore reserves behind. In 2021 after completion of mining in another part of the pit, a plan was formulated to develop a narrow cutback behind the failed wall and recover the sterilised ore. Infill drilling defined a resource of approximately 2.9 Mtonne (3.2 Mton) of ore at 0.78% Cu and 0.67 g/t Au at a strip ratio of 5.5:1. The high strip ratio meant that it was necessary to mine thirteen benches of waste, or 156 m (512 ft) vertically, over a two-year period before reaching the first ore, with the cutback only being economically viable if all ore could be depleted at the end of the third year. The high economic risk of the project required a holistic approach to mitigate the risk of another wall failure, by addressing the following areas: 1. Pit Design: with help from an external Geotechnical Consultant, the pit design was optimised to include increased factors of safety, reduced stress points, lower overall slope angles and straight lined walls were replaced with curved walls. 2. Geotechnical Management: the site Geotechnical Superintendent worked closely with an external Geotechnical Consultant to better understand the structural geology. Slope monitoring was improved through an expanded network of prisms, regular in field inspections and the use of a slope monitoring radar. 3. Drill and Blast: new drill and blast designs were developed from first principles, consisting of production, wall control and presplit designs. Blast master polygons and bench development sequences were developed with consideration of the structural geology and the influence of the initiation designs. 4. Mine Operations: improving operational discipline was a critical factor that ensured the accurate execution of drill and blast designs and excavation to bench levels and pit limits. This holistic approach has enabled the safe development of the cutback down to the 936 RL (relative level), two benches below the point at which the previous wall failure occurred. Extraction of ore has occurred from the 960 RL, and due to faster than planned excavation rates, the cutback is expected to be completed ahead of schedule.

Jan 21, 2025

By R W. Thomas

This paper explores the possibilities of generating radical improvements in the drilling costs and productivity of blastholes through the efforts of integrated teams as opposed to traditional customer/vendor relationships.

Jan 1, 1996

By Robert Hopler

SECTION 9.---BORING AND BLASTING.*155. Blasting is the operation of bringing down and detaching from its bed or position masses of material by means of explosives.

Jan 1, 2011

By Jerry Wallace

Two recent-release boulders posed serious threats to public transportation and utilities in Washington State. Both required challenging drilling and blasting solutions.

Jan 1, 1997