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Abrasive blasting process optimization is aimed at establishing relationships between applied feed rates and resulting productivity and consumption rates. It is clear that the high costs of disposal of the multimedia wastes generated by the dry abrasive blasting processes are of increasing concern in the future of shipbuilding industry. In such circumstances essential care has to be given to all components of the process to enhance productivity and decrease consumption rates. This study discusses most of the process components and their respective effects on blasting productivity and consumption rates briefly and concentrates on two important process parameters, nozzle pressure and abrasive feed rate. Feed rate is a vital process parameter that contributes to the productivity and consumption rates of the process. Subsequently feed rates also can significantly impact the costs bore by Shipbuilding Industry in the form of disposal and environmental costs. Most commonly used abrasives were identified through a rigorous survey and were opted to be used in this study. The approach adopted to develop the relationships consists of a mass balance equation between the expended abrasives and disposed wastes to clean a predetermined area of a plate. The obtained data was further analysed to develop productivity rates and consumption rates for each sample runs. The data was then evaluated to formulate relationships that would enable the derivation of optimum feed rates for desirable productivity and reduced waste generation.

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2017 / The study sought to establish the applicability of rock mass classification as a primary input to wall control blasting. Conventional rules of thumb are used to develop blast designs based on parametric ratios with insufficient consideration of the rock mass factors that influence the achievability of final wall designs. Control of the western highwall of the Phoenix pit had proven to be challenging in that the designed catchment berms and wall competence were perpetually unachievable from the pit crest to the current mining levels. This exposed the mining operation to safety hazards such as local wall rock failure from damaged crests, frozen toes and rolling rock falls from higher mining levels. There was also an effect of increased standoff distances from the concerned highwall which reduce the available manoeuvring area on the pit floor and subsequently the factor of extraction that is safely achievable. The study investigated the application of rock mass classification and the Blastability Index (BI) as a means to improve wall control. This was achieved by establishing zones according to rock type forming the western highwall rock mass wherein distinguishing rock mass classification factors were used to establish the suitable wall control designs through a Design Input Tool (DIT). The DIT consolidated rock mass classification methodologies such as the Geological Strength Index (GSI) and the Rock Mass Rating (RMR) and related them to the BI and discontinuities of the rock mass to produce a tool that can be used to develop objective wall control designs. The designs driven by the tool inherently take into account the rock mass characteristic factors at the centre of rock mass classification methods and significantly reduce the dependence on rule of thumb. It was found that this approach yields designs with powder factors that are consistent with the rock breaking effort and the behaviour of discontinuities while remaining biased towards preservation of perimeter wall rock. / MT 2017

PhD, Faculty of Engineering and the Built Environment, School of Mining Engineering, University of the Witwatersrand, 2003

Drilling and blasting are seen as sub-systems of size reducing operations in mining. To have better design parameters for economical excavation of mineral production and fragmentation, the comminution and fragmentation operations need to be studied and optimized independently, as well as together, to create optimized use of energy and cost-effective operation. When there is a change in drillhole diameter or fragmentation specification, changes in the blast design parameters are required affecting the cost of a drilling and blasting operation. A model was developed to calculate blast design parameters and costs on the basis of the required 80% fragment size needed for crusher operation. The model is based on previously developed fragmentation models, found in the literature. The model examines the effect of drilling diameter on blasting requirements to achieve certain fragmentation targets and calculates blast design parameters and costs for a range of diameters from 75 to 350 mm. To examine the effectiveness of this model, two different 80% passing sizes of fragments have been considered. It was shown that cost optimization occurs at an intermediate diameter, since there are opposing trends of the effect of diameter on powder factor and accessories needed. To achieve a certain fragmentation target, the total cost of drilling and blasting shows a clear trend allowing an optimum selection of diameter. The selected diameter also allows the examination of the suitability of the drill machine under the given geological and operational conditions of the drilling site. / Thesis (Master, Mining Engineering) -- Queen's University, 2009-03-27 07:34:33.787

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Thesis (M.S.)--Oregon State Agricultural College, 1936. / Typescript. Includes bibliographical references (leaves 124-130). Also available on the World Wide Web.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Few studies of blasting exist because of difficulties in obtaining reliable fragmentation data or even obtaining consistent blasting results. Many researchers have attempted to predict blast fragmentation using the Kuz-Ram model, an empirical fragmentation model suggested by Cunningham. The purpose of this study is to develop an empirical model to relate specific explosives energy (ESE) to blasting fragmentation reduction ratio (RR) and rock fracture toughness (KIC). The reduction ratio was obtained by analyzing the bench face block size distribution and the muck fragment size distribution using image analysis. The fracture toughness was determined using the Edge Notched Disk Wedge Splitting test. Blasting data from twelve (12) blasts at four (4) different quarries were analyzed. Based on this data set, an empirical relationship, ESE=11.7 RR801.202 KIC4.14 has been developed. Using this relationship, based on the predicted blasting energy input for a desired eighty-percent passing (P80) muckpile fragment size the burden and spacing may be determined. / Master of Science