110 research outputs found
Gravity flow of broken rock : What is known and unknown
No full textThe knowledge in the field has been reviewed by literature studies, and using experience from personal research in sublevel caving. There is a lot of material regarding gravity flow of fine grained materials in bins, but the theory of flow for these materials are normally not applicable for coarse blasted rock. This study was therefore concentrated towards coarse rock fragments created after blasting in orebodies. The goal for this study was to make a report of known knowledge, and identify what we have to learn more about. The Bergmark-Roos theory, which was a paradigm shift in the science of gravity flow, is today the best mathematical theory for calculation of the drawbody for a homogenous material or when we wish to simulate the mean drawbody for a large number of draws. The Bergmark-Roos theory must however be improved, so it can take into account the flow pipe effect. When this is done it will be possible to construct a 3D computer model for calculation of ore extraction versus amount of loaded ore and waste. It is also necessary to find the 3D shape of the flow cone to be able to calculate the 3D ore rest that normally develops on footwalls. Calculations should be done for the draw on several sublevels including determination of the ore losses and temporary ore rests. First when this computer model is developed optimisation of ore recovery and waste rock dilution can start for a given orebody. The author points out the importance for international co-operation and standardisation of methods for determination of material properties. More field tests and model blasting tests should also be done. When enough knowledge is gathered, a handbook of the optimisation of sublevel and block caving should be written</p
Automatic image processing and analysis of rock fragmentation-comparison of systems and new guidelines for testing the systems
No full textThe development of an automatic image processing and analysis system for rock fragmentation was started in Lulea in the beginning of the 1980's and the result was presented at Fragblast 1 (First International Symposium on Rock Fragmentation by Blasting) in Lulea in 1983. Since that, many countries like; Australia, Canada, France, Germany and USA have started their own development of automatic image processing and analysis systems. The ISRM Commission on Fragmentation by Blasting found that the time had come to make a state of the art report of the technique and the former ISRM President John Franklin was asked to arrange a workshop in connection to Fragblast 5 in Montreal in co-operation with Takis Katsabanis from Queens University, Ontario, Canada. Some principal data from Automatic image processing and analysis systems presented at the workshop are collected and compared in this paper. Also strategic issues regarding fragmentation analysis and the presentation of fragment size distributions, which were posted by the author of this paper in the poster session at Fragblast 5, are discussed after getting feed back from the participants. A proposal for an international testing procedure of the accuracy of the automatic image processing and analysis systems is presented.</p
Controlled fragmentation and contours in rock blasting [Elektronisk resurs] : theoretical and technical approaches
No full textThe Swedish mining and construction industries have a large interest in improving blasting technology, in milling concerning rock fragmentation by blasting (especially underground in large diameter hole blasting, > 100 mm) and in construction and mining concerning controlled and safe contours in blasted tunnels. This doctoral thesis deals with these matters and includes a licentiate thesis (published in 1970) and five papers A-E included in the doctoral thesis and published during 1983 to 1992. The licentiate thesis (in Swedish) presents the development of a method to determine the ore content in an LHD-bucket after loading iron ore in the mine. The method is based on measuring the bulk density of the ore-waste mixture. In order to investigate the accuracy of the method a theoretical model was established, and verified by model-scale blasting tests and research concerning fragmentation and swelling of blasted ore under varying technical and environmental conditions. Paper A describes a part of the licentiate thesis, the development and choice of a suitable model material for the blasting tests. Controlled Contour Blasting Technique (Paper B) especially in tunnelling, needs improvement in bad rock. Literature studies and model and full-scale tests were the base for the evaluation of the existing and proposed contour blasting methods. Controlled Rock Fragmentation (Paper C, D, and E) is an important goal, especially in large hole diameter blasting. New design formulas were therefore developed for mean fragment size, rock fragment size distribution, etc. in connection with technical parameters such as burden or specific charge, spacing and rock impedance. The formulas are based on literature studies and model and flill-scale tests. A new relation between the burden and blasthole diameter was derived from statistical analysis of data from one hundred surface and underground mines. The relation is different for surface and underground mines.</p
Improvement of the Fonematological Perception for 6-year-old Children Using Information and Communication Technologies
No full textDiplomdarba nosaukums: “Fonemātiskās uztveres pilnveide 6 gadīgiem bērniem, izmantojot informācijas un komunikāciju tehnoloģijas”. Darba autore: Agne Berga. Darba zinātniskā vadītāja: Mg. paed. Egija Laganovska. Darba saturs: 57 lpp., 14 attēli, 5 tabulas, 16 pielikumi. Pētījuma mērķis: izzināt un pārbaudīt fonemātiskās uztveres pilnveides iespējas 6 gadīgiem bērniem, izmantojot informācijas un komunikāciju tehnoloģijas. Pētījuma hipotēze: 6 gadīgu bērnu fonemātiskās uztveres traucējumu koriģējoši attīstošā darbība ir sekmīgāka, ja: •tiek ievērotas bērna vecumposmam un runas attīstības individuālās īpatnības, •koriģējoši attīstošā darbā tiek izmantotas informācijas un komunikāciju tehnoloģijas. Pētījuma teorētiskajā daļā diplomdarba autore analizē un apraksta bērna attīstību veselumā (fizisko, emocionālo, sociālo, kognitīvo attīstību), kā arī fonemātiskās uztveres attīstību, informācijas un komunikāciju tehnoloģiju, to izmantošanu fonemātiskās uztveres pilnveidē. Darba praktiskajā daļā autore apraksta savu pētnieciski praktisko darbību pirmsskolas izglītības iestādē, kas balstīta uz teorētiskajā daļā gūtajām atziņām. Pētījuma rezultātā tiek izdarīti secinājumi un ieteikumi logopēdiem. Pētījuma rezultāti tiek apkopoti tabulās un attēlos. Atslēgas vārdi: fonemātiskā uztvere, pirmsskolas, informācijas un komunikāciju tehnoloģijas, interaktīvi uzdevumi, 6 gadīgi bērni. The title of the diploma thesis: “Improvement of the Fonematological Perception for 6-year-old Children Using Information and Communication Technologies” The author of the work: Agne Berga The scientific supervisor: Mg. paed Egija Laganovska Content of the work: 55 pages, 14 pictures, 5 tables, 16 annexes The objective of the study: to find out and to check the possibilities of improvement of the phonological perception for 6-year-old children using information and communication technologies. The hypothesis of the study: the corrective development activity of the phonemic impairment in children age 6 is more successful if: •the child's age and individual peculiarities of speech development are respected, •information and communication technologies are used in the corrective developing work. In the theoretical part of the research, the author of the diploma paper analyses and describes the development of the child on the whole (physical, emotional, social, cognitive development) as well as the development of phonemic perception, information and communication technology, their application in the improvement of phonemic perception. The practical part of the work contains the description of the study carried out by the author during her work in a pre-school educational establishment based on the propositions gained in the theoretical part. Having carried out the study the author made conclusions and provided the suggestions for speech therapists. The results of the study are summarized in tables and images. Keywords: phonemic perception, preschool, information and communication technologies, interactive tasks, children 6 years old
Försiktig och skonsam sprängning under jord : diskussionsdagar i Luleå 17-18 september 1980
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