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By Thomas A. Simpson, Yung-Kwaun Jow, Dennis L. Gamble

Construction of the $200 million Riverchase Galleria Mall in Hoover, Alabama was started in early 1984. The construction area consists of about 70 acres. The extensive building complex requires heavy concrete foundations which have to be poured during the early stages of construction and on a nearly daily situation so that contractual agreements can be met on a timely basis.

Jan 1, 1985

By Sally Lynn Zadra

"In May, 1994, Echo Bay Minerals - McCoy/Cove Mine petitioned for approval to recycle used oil formanufacturing ANFO. Recycling oil in this way will result in a cost savings for the minesite as well ashaving a positive environmental effect The petition has met the approval of the Bureau of LandManagement, the Nevada Department of Environmental Protection, and has received tentative approval from the Mine Safety and Health Administration."

Jan 1, 1996

By P. D. Katsabanish

Air decking applications are examined using numerical modelling and the AutodynTM code. The mechanism of damage is illustrated and discussed. Air decking is shown to provide advantages over stemming when powder factor is maintained. The current effort does not support reduction of the explosives column in favour of air decking. In a similar fashion, bottom hole air decking increases fracturing in the area of the air deck, compared to when the same volume is occupied by inert materials; however air decking does not appear to reduce the requirement for subdrilling. The apparent discrepancy between the numerical results and some field observations reported in the literature is discussed.

Jan 1, 2005

By V Krishna Mohan, J Edmund Hay

This paper discusses the results of the gap sensitivity measurements made on water-gel explosives, sensitized by monomethylamine nitrate (MMAN) and flake aluminium, and one emulsion explosive. This study specifically deals with the effect of the mode of initiation, end or center, on the measured L50 values with air gap and coal dust gap for the above explosives. Similar measurements have also been carried out on a nitroglycerine (NG) - based explosive. The results show that the mode of initiation plays an important role in determining the air-gap sensitivity of these explosives. However, in tests carried out with the coal dust gap, the L50 ( grams of coal dust ) values for these explosives are close in both the types of initiation. The results indicate that the sensitivities of these explosives may be ordered in the following manner: NG-explosive>> Aluminized explosive ~ MMAN-explosive > Emulsion explosive

Jan 1, 1982

By Brian Wingfield, Rick Givens, Greg Williams

Many technological advancements have been made in explosive products and applications over the last 15 years resulting in productivity and cost gains. However, the application of total energy (engine horsepower) in the majority of rotary drilling technology, has remained virtually unchanged over that period. While advancements have been made in components, efficiency, and types of hydraulic systems used on drills, the application of current hydraulic technology to improve drilling productivity has not been interactive with end users.

Jan 1, 1996

By John C. Didlinger, John L. Didlinger

As we begin the pre-blast survey we need to decide on the number of holes needed for production and a detailed highwall inspection. The survey consists of checking the highwall and placement of barrier cones. At the Elmhurst Chicago Stone Company, Barbers Corner Plant, we use 18-24" orange highway type safety cones. These cones are easily noticed because of their high visibility color in all weather conditions and are placed approximately 20-25 feet from the face and approximately 50 feet apart along the highwall, then the area is checked for back break, under cut, over hang, surface filled area and clay area. This deposit is unique because of the number of clay filled areas and slip seams that meanders through the deposit plus a fault that runs North-Northwest and South-Southeast. This particular limestone deposit is overlaid with glacial sand and gravel and the top weathered stone wanders plus or minus 10 feet in 1400 feet.

Jan 1, 1996

By R L. Keller

Hong Kong has some of the most restrictive practices regarding blasting than any place in the world. Regulations regarding vibration limitations are 1 in/sec for structures and 0.5 in/sec (or even less) for most utilities; with no recognition of frequency response or adjustment. The Hong Kong Geotechnical Engineering Office has one of the most conservative approaches and protective guidelines for pre-blast assessment of slopes subjected to blast vibration (SEE paper '96). The protective measures to control flyrock generally required by the Mines Division are additionally very stringent. It is not uncommon for the costs associated with protective measures or methods which must be employed to exceed the cost of the drilling and blasting itself - or to waiver blasting application unfeasible altogether. From these restrictions it can easily be imagined how blasting in this urban environment would be most challenging.

Jan 1, 1997

By Michael Karmis, Syed Muhammad Tariq, Zeshan Hyder

Secondary or boulders blasting is a regular feature of quarrying operations in Pakistan, especially in cement and stone crushing industries. The main reason for secondary blasting is the production of a large number of boulders during the production blast. These boulders are larger than the feed hopper of crushers and require further breaking. The complex geometry of boulders, relative lack of restraining burdens, and the availability of number of free faces make this kind of blasting more hazardous than production blasting. Secondary blasts have generally unpredictable results and may cause flyrock, airblast, and over-crushing of rock material. Thus, it is essential to have an appropriate amount of explosive charge/powder factor, and for it to be properly distributed in the blast hole. The greater the amount of explosive over the required amount, the more violent is the blast, which will result in more flyrock, airblast, and excessive crushing of boulders.

Jan 1, 2012

By Paul L. Matrin

This paper will discuss the recent and on-going drill and blast optimization measures at the Sparkhule Limestone Quarry, which have resulted in a 44% reduction of drill and blast unit costs per ton of broken limestone. This amounts to approximately $240,000 of drill and blast saving per year at current annual production rates of about 2.5 million tons (2.3 million tonnes) total material shot. The reduction of drill and blast costs were accomplished by a detailed and controlled in-the-mine drill/blast experimentation and cost evaluation using 8 different blast pattern designs and shots totaling approximately 267,000 tons (242,200 tonnes) of shot and mucked material. A careful review of the geology of the deposit was performed to determine the different rock classification/strengths/structural properties and to adjust blast designs to optimize fragmentation for the different rock types. Equipment loading productivity and crusher throughput performance were monitored as part of the evaluation process to assure that an optimal fragmentation of broken rock was achieved with the new blast designs. The study included the review of bulk explosive and accessory selection criteria (ammonia nitrate/fuel oil mix - ANFO, mini prills (high density ANFO), sensitized and un-sensitized emulsions at a 30% emulsion/70% ANFO blend), blast pattern design, charge diameter and the cost of drilling. Laser profiling technology was used to assure proper bench heights, stemming and sub-drill footage and front row burdens. High speed photography, video and still photos were taken of the different designed shots to assist in the evaluation of the performance of each blast. Powder density checks, size distribution, back break, detonation velocity and pressure measurements were taken. Different borehole diameters were used for the drill optimization study and drilling cost and productivities determined. A detailed cost comparison between in-house blasting and complete shot service was prepared to evaluate if shot service is a cost effective alternative to current in-house loading and blasting including a review of the new and pending United States Bureau of Alcohol, Tobacco and Fire Arms (ATF) regulations and associated owner costs/risks and potential benefit of shot service.

Jan 1, 2004

By Melvin A. Sannes

The explosives industry is recognized as one of the most dangerous occupations in the world, yet it is rare to see actual training procedures. As our industry becomes increasingly technical, it is imperative that we train the personnel in OUI industry properly.

Jan 1, 1999

By Jim Simpson, John Waller, Scott Stewart

The authors review the evolution of drilling and blasting procedures at this West Virginia surface coal mine where management seeks continually to improve and update the drilling and blasting programs. Today's operations require efficient programs which include quality control to maximize production and minimize the public's sensitivity to the blasting events.

Jan 1, 1992

By P D. Katsabanis

Explosives malfunction due to shock waves is a serious concern for successful blasting results. Malfunction includes sympathetic detonation and desensitization of explosive charges as well as the modification of firing times of conventional pyrotechnic detonators.

Jan 1, 1995

By J Lyall Workman, Peter N. Calder

Flyrock can be a serious hazard associated with blasting. Many surface blasting accidents involving injury result from excessive flyrock beyond the protected blast zone. Numerous cases of equipment damage at the mine, quarry or construction site have resulted from flyrock. Fragments propelled beyond the property limits of the operation have also caused injury and damage.

Jan 1, 1994

By Dave I. McGregor

The Multiple Raise Round Blasting Technique (MRRBT) is a safe, efficient, cost effective method of blasting thee will use existing mine personnel. The MRRBT, developed from the conventional 'drop raise method' style of blasting, can be used for most raise mining applications. Current results using MRRBT indicate no upper limit for the maximum length that a raise can be blasted.

Jan 1, 1994

By Norman S. Smith, Troy D. Harris, Richard L. Ash

In open-cut bench blasting drilling boreholes below grade level is normally considered essential to insure toes do not remain. The extra drilling and use of explosive below floor level are not only expensive but on occasion cause serious problems including severe floor damage and excessive ground vibrations. It has been reported that under certain circumstances explosive in the subdrilling has been successfully substituted by broken rock with its associated benefits.

Jan 1, 1978

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 Zoltan Susanszky

Technical development in blasting requires improvement of industrial explosion techniques in two fields. One is to apply increasingly exact and economical solutions with more effective explosives, the other is to restrict as much as possible the environmental effect of explosions.

Jan 1, 1978

By D T. Froedge

A new system for acquiring blast vibration data and a method for presenting that data in such a way that there can be an extraordinarily enhanced insight into the understanding of vibrations produced by blasting is described in this paper.

Jan 1, 1989

By John Turner, James Lamb

The Minnesota Department of Transportation (MNDOT) has an extensive project to improve driving conditions and reduce hazards to motorists on US Highway 61 between Duluth, MN, and Canada along the north shore of Lake Superior. In 1991, the Lafayette Bluff Tunnel was completed just north of Two Harbors, MN, through a joint venture of Johnson Brothers Corporation of Litchfield, MN, and Obayashi Corporation of San Francisco, CA.

Jan 1, 1994

By Guang-Xin Li, Rui-Ping Guo

Based on the analysis of factors affecting the cracking performance of Silently Cracking Agent (SCA), a new SCA structural model is built and a study on the swelling mechanism of SCA and a method to increase swelling thrust by adding the swelling agent are presented. The reason for blow-out and the theory for avoiding blow-out are put forward. The new model improves the SCA theory and provides new method for developing effective SCA. Based on experiments made in laboratory, two types of SCA are developed. A Temperature Control Meter (TCM) has been developed to solve the alltemperature- crack problem after studying the suitable temperature scope of SCA.

Jan 1, 2000