In this research, we investigated the influence of rock mass properties, blast design parameters and explosive properties on blast fragmentation. Rock mass properties were evaluated in 51 blasting blocks using enginee...In this research, we investigated the influence of rock mass properties, blast design parameters and explosive properties on blast fragmentation. Rock mass properties were evaluated in 51 blasting blocks using engineering geological mapping of 1961 meters of the scanline, experiments on intact rock samples and measuring P-wave velocity(Vp) for 1771 meters of seismic profiles. The results indicate that increasing spacing, persistence, opening, roughness, waviness of discontinuities, and Vp and uniaxial compressive strength(UCS) of intact rock as well as the increase of discontinuities angle with the bench face of blasting block will increase the size distribution of blasted rocks. In addition, evaluation of the influence of connector type, specific drilling and specific charge has shown that using the Nonel system will decrease the mean size of fragmentation. It is also demonstrated that increasing specific drilling and specific charge quantities will result in the increase of mean size of fragmentation.展开更多
Selection of the crusher required a great deal of design regarding to the mine planning. Selection of suitable primary crusher from all of available primary crushers is a multi-criterion decision making(MCDM) problem....Selection of the crusher required a great deal of design regarding to the mine planning. Selection of suitable primary crusher from all of available primary crushers is a multi-criterion decision making(MCDM) problem. The present work explores the use of technique for order performance by similarity to ideal solution(TOPSIS) with fuzzy set theory to select best primary crusher for Golegohar Iron Mine in Iran. Gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impact crusher, hammer mill and feeder breaker crushers have been considered as alternatives. Also, the capacity, feed size, product size, rock compressive strength, abrasion index and application of primary crusher for mobile plants were considered as criteria for solution of this MCDM problem. To determine the order of the alternatives, closeness coefficient is defined by calculating the distances to the fuzzy positive ideal solution(FPIS) and fuzzy negative ideal solution(FNIS). Results of our work based on fuzzy TOPSIS method show that the gyratory is the best primary crusher for the studied mine.展开更多
On the basis of the study on the engineering geological characteristics of No.2 dump of Nanfen iron mine and the analysis of the failure mode of dump landslide,the stability of the present dump,the stability of the du...On the basis of the study on the engineering geological characteristics of No.2 dump of Nanfen iron mine and the analysis of the failure mode of dump landslide,the stability of the present dump,the stability of the dump 20 years later and the stability of double-bench dump are analyzed.Then,the debris flow risk is evaluated by fuzzy mathematics method.Finally,the comprehensive treatment for the dump is suggested.It is concluded that ① In rainy and snowmelt period,the stability would be decreasing sharply when ground water is not drained out in time;② Double-bench dumping mode will improve stability of the dump little;③ Debris flow risk is middle danger.The interim debris flow with medium scale may occur.④ Monitoring,draining and baffling work ought to be well done.⑤ In order to prevent the damage of landslide and debris flow,three measures are adopted,including setting rockfall net,setting the debris flow barrier and removing the residents.展开更多
文摘In this research, we investigated the influence of rock mass properties, blast design parameters and explosive properties on blast fragmentation. Rock mass properties were evaluated in 51 blasting blocks using engineering geological mapping of 1961 meters of the scanline, experiments on intact rock samples and measuring P-wave velocity(Vp) for 1771 meters of seismic profiles. The results indicate that increasing spacing, persistence, opening, roughness, waviness of discontinuities, and Vp and uniaxial compressive strength(UCS) of intact rock as well as the increase of discontinuities angle with the bench face of blasting block will increase the size distribution of blasted rocks. In addition, evaluation of the influence of connector type, specific drilling and specific charge has shown that using the Nonel system will decrease the mean size of fragmentation. It is also demonstrated that increasing specific drilling and specific charge quantities will result in the increase of mean size of fragmentation.
文摘Selection of the crusher required a great deal of design regarding to the mine planning. Selection of suitable primary crusher from all of available primary crushers is a multi-criterion decision making(MCDM) problem. The present work explores the use of technique for order performance by similarity to ideal solution(TOPSIS) with fuzzy set theory to select best primary crusher for Golegohar Iron Mine in Iran. Gyratory, double toggle jaw, single toggle jaw, high speed roll crusher, low speed sizer, impact crusher, hammer mill and feeder breaker crushers have been considered as alternatives. Also, the capacity, feed size, product size, rock compressive strength, abrasion index and application of primary crusher for mobile plants were considered as criteria for solution of this MCDM problem. To determine the order of the alternatives, closeness coefficient is defined by calculating the distances to the fuzzy positive ideal solution(FPIS) and fuzzy negative ideal solution(FNIS). Results of our work based on fuzzy TOPSIS method show that the gyratory is the best primary crusher for the studied mine.
文摘On the basis of the study on the engineering geological characteristics of No.2 dump of Nanfen iron mine and the analysis of the failure mode of dump landslide,the stability of the present dump,the stability of the dump 20 years later and the stability of double-bench dump are analyzed.Then,the debris flow risk is evaluated by fuzzy mathematics method.Finally,the comprehensive treatment for the dump is suggested.It is concluded that ① In rainy and snowmelt period,the stability would be decreasing sharply when ground water is not drained out in time;② Double-bench dumping mode will improve stability of the dump little;③ Debris flow risk is middle danger.The interim debris flow with medium scale may occur.④ Monitoring,draining and baffling work ought to be well done.⑤ In order to prevent the damage of landslide and debris flow,three measures are adopted,including setting rockfall net,setting the debris flow barrier and removing the residents.
