Comparison of the existing and calculated blast design parameters for the rock mass conditions at Bamesso-Latet rock quarry

Blasting is the most cost effective methodology to break rock for mining engineering applications. A good production blast will break only the rock that is needed to be removed, leaving the host rock with minimal damage. Accurate measurement of blast, fragmentation is important in mining and quarrying operations, in monitoring and optimizing their design. Currently, there are several methods available to predict damage due to blasting. The accuracy of many of these methods is questionable, and in most cases, the methodologies over predict the results. This paper presents a practical method (i.e. Langefors’s method) that we shall use in Bamesso-Latet rock quarry to do a comparison between the existing and calculated blast design parameters. The proposed method allows to assess the rock damage from blasting. It shows great potential as a practical aid to control and get a good quality of the fragmented material in Bamesso-Latet rock quarry.

Sustainability Analysis of Marble Sector in Buner

Marble is an ornamental stone, extremely popular for use as architectural and sculptural purposes. Nonrenewable marble resources in Khyber Pakhtunkhwa (KP), Pakistan are mostly mined by conventional mining methods(producing irregular shaped blocks) instead of using mechanized mining producing regular shaped blocks.Conventional mining methods are more economical but are less environment friendly due to more quantity of wasteproduced. While, mechanized marble mining has a better recovery, reduces mining cost (processing and transportation)and is less environmentally hazardous. In this study a situation and sustainability analysis of marble mining operationsat Buner, the most productive marble mining cluster in KP, Pakistan, is carried out. Buner has about 1.4 billion tons ofmarble resources and contributes around 51 percent of total country’s marble production. Analytical Hierarchy Process(AHP) is used on the basis of key sustainability factors (economic, technical, social, environmental and safety) forselection of most sustainable mining methods. The analysis revealed that conventional mining is least sustainable andproduces maximum waste, cracks, irregular shaped blocks, high working faces, back break, rock falls and accidents. Itwas concluded and recommended that these conventional mining methods should be replaced with the more sustainablemining methods i.e. semi-mechanized (controlled blasting / expansion material) at sunny grey and get black marbledeposits and mechanized mining (rope cutting) at Bampokha No.1 and Chagharzai white marble deposits.

Sustainability Analysis of Marble Sector in Buner

Marble is an ornamental stone, extremely popular for use as architectural and sculptural purposes. Nonrenewable marble resources in Khyber Pakhtunkhwa (KP), Pakistan are mostly mined by conventional mining methods(producing irregular shaped blocks) instead of using mechanized mining producing regular shaped blocks.Conventional mining methods are more economical but are less environment friendly due to more quantity of wasteproduced. While, mechanized marble mining has a better recovery, reduces mining cost (processing and transportation)and is less environmentally hazardous. In this study a situation and sustainability analysis of marble mining operationsat Buner, the most productive marble mining cluster in KP, Pakistan, is carried out. Buner has about 1.4 billion tons ofmarble resources and contributes around 51 percent of total country’s marble production. Analytical Hierarchy Process(AHP) is used on the basis of key sustainability factors (economic, technical, social, environmental and safety) forselection of most sustainable mining methods. The analysis revealed that conventional mining is least sustainable andproduces maximum waste, cracks, irregular shaped blocks, high working faces, back break, rock falls and accidents. Itwas concluded and recommended that these conventional mining methods should be replaced with the more sustainablemining methods i.e. semi-mechanized (controlled blasting / expansion material) at sunny grey and get black marbledeposits and mechanized mining (rope cutting) at Bampokha No.1 and Chagharzai white marble deposits.

Breaking it Down: Mechanical Processes in the Weathering Engine

The vast diversity of landscapes found on Earth results from interplay between processes that break rock down, produce mobile regolith, and transport materials away. Mechanical weathering is fundamental to shaping landscapes, yet it is perhaps less understood at a mechanistic level than chemical weathering. Ubiquitous microfractures in rock propagate and grow through a slow process known as subcritical cracking that operates at the low applied stresses common in the near-surface. Subcritical cracking is the most likely explanation for the mechanical processes associated with thermal stress, ice lens growth, mineral alteration, and root growth. The long timescales over which critical zone architectures develop require an understanding of slow processes, such as subcritical cracking.

Analysis of the Cavity Formation Mechanism of Wedge Cut Blasting in Hard Rock

The basic process of cut blasting is to break rock, throw fragments, and form a cavity. Based on the characteristics of cut blasting and the combined effect of stress waves and detonation gas, the evolution process of wedge cut blasting is divided into two stages, and a theoretical model is proposed to investigate the cavity formation mechanism by theoretical analysis and field tests. In phase one, rock breaking is caused by stress waves. By considering the dynamic strength of the rock, a computational model is built for the rock failure zone derived from the coupled cylindrical charge explosion. In phase two, the driving force of the detonation gas overcomes the total resistance of the surrounding rock mass, accelerates fragments, and then throws fragments to form a cavity. The criterion of cavity formation is established on the basis of the quasi-static loading of the detonation gas. The theoretical model provides an overall interpretation of the cavity formation mechanism, in which stress waves break rock and detonation gas throws fragments. A specific case indicates that the range of the failure zone is approximately 18 times the borehole radius in granite and that the hole-bottom spacing of the wedge cut can be designed as 50 cm; in addition, detonation gas is sufficient to overcome the total resistance, accelerate rock fragments, throw fragments, and form a cavity. Field tests present favourable blasting results, with a high utilization rate of boreholes and uniform fragment sizes. Therefore, the model could provide theoretical support and technical guidance for wedge cut blasting in hard rock.

Experiment on Conical Pick Cutting Rock Material Assisted with Front and Rear Water Jet

Conical picks are one kind of cutting tools widely used in engineering machinery. In the process of rock breaking, the conical pick bears great cutting force and wear. To solve the problem, a new method, conical pick assisted with high pressure water jet, could break rock effectively, and four different configuration modes of water jet were presented. In this paper, based on the analysis of the different water jet configuration’s advantages and disadvantages, experiments on front water jet, new typed rear water jet, and the combination of those two water jet configuration modes were conducted to study the assisting cutting performance and obtain the quantitative results.

An Investigation on Sand Production of Vertical Shaft Impact Crusher Using EDEM

Discrete element modeling (DEM) is the most suitable modeling technique to simulate the mass flow of particles in chamber recently, which is an important part of VSI to break rock. DEM is presented in this message to predict sand production within a US7 vertical shaft impact crusher. Sand production is one of important parameters to judge the productiveness of VSI. Despite complicated particle movements in vertical shaft impact crusher, it is a necessary work to study the sand production of VSI. Vertical shaft impact crusher is simulated under different conditions in EDEM software.In order to investigate effects of different parameters on sand production, four parameters which include rotor rotation, inputs, radius of particle and interval between the rock bed and throwing material hammer were separately set into simulation tests.

Optimization Design of Self-Excited Oscillation Cavity

Along with the over exploitation of oil and gas resources, complicated reservoirs should be exploited in abominable environments. New drilling methods, drilling tools and drilling crafts for breaking rock are urgently needed. In drilling project, opening radial holes in the wall of self-excited oscillation cavity, more drilling fluid absorbed from annulus and more hydraulic energy could be obtained to break rock efficiently. Therefore, in this paper, self-increasing flux of cavity with different velocity in annulus, ratio of upper and lower nozzle diameters and diameter of aperture were simulated using CFD numerical method. Then flow fields in different aperture conditions and the best aperture parameter were obtained. Some references can be provided to actual drilling for further better jet breaking rock and improving drilling speed, which also have a good economic benefit.