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Underground hard rock (metal/non-metal) mining
Published in A.J.S. (Sam) Spearing, Liqiang Ma, Cong-An Ma, Mine Design, Planning and Sustainable Exploitation in the Digital Age, 2023
A.J.S. (Sam) Spearing, Liqiang Ma, Cong-An Ma
Figure 3.42 shows a schematic picture of the alignment of the underground workings in block caving relative to the stresses. Parallel drifts are developed through the orebody on two main levels: the undercut level and the production level. In a later step, the undercut initiation is conducted out of these drifts by drilling into the roof with blasting. This weakens the groundmass directly. The breaking rock reaches the loading drifts of the production level via draw bells. The production level is characterized by a grid pattern of drifts consisting of the loading drifts and haulage crosscuts. This enables a consistent distraction of the ore. The broken ore (muck) is carried by LHD from the drawpoints to the collection points (ore-passes), which let the muck travel down to the haulage level to be moved to the surface using a conveyor belt in a decline or hoisted in a vertical shaft. Often a crusher is included to reduce the maximum size to one that will not block the ore-passes and can be safely handled by the equipment suite. The haulage level is connected to ramps or shafts, to convey the material out of the mine.
Origin, Usage and Production of Unbound Granular Materials for Road Construction
Published in A. Gomes Correia, Fernando E.F. Branco, Bearing Capacity of Roads, Railways and Airfields, 2020
G. Bjarnason, H.G. Johansson, S. Davitt
The following types of crushers have been identified as being used in the production of unbound base, sub-base, or capping layer materials for road pavements in Europe: Jaw CrushersGyratory CrushersImpact Crushers, including Vertical Shaft ImpactorsCone Crushers.
A study on haulage technology and equipment in large open pit mines in China
Published in Vladimír Strakoš, Vladimír Kebo, Radim Farana, Lubomír Smutný, Mine Planning and Equipment Selection 1997, 2020
(2) Crushing machine’s failure and crusher clogging. The mechanical breakdown of crasher is resulted not only from manufacturing technology but from Inappropriate usage. The clogging reason of crusher is that the speed and position of passed materials can’t being controlled exactly. Thus the speed of passed materials should be controlled strictly.
A review on recycled concrete aggregates (RCA) characteristics to promote RCA utilization in developing sustainable recycled aggregate concrete (RAC)
Published in European Journal of Environmental and Civil Engineering, 2022
Aamar Danish, Mohammad Ali Mosaberpanah
Concrete waste can be crushed by various crusher types like jaw, impact, hammer mill and cone crusher (Li, 2008). The selection of crusher type for each stage of recycling depends upon factors like feed size, quality, size, shape and fines. All mentioned crusher types have various impacts on physical and/or mechanical properties of resulted RCA (Matias et al., 2013) which eventually affects the properties of its products (concrete and mortar). For example, the crushers which convert big sized concrete waste blocks into smaller fragments to be fed into secondary crusher are generally jaw crushers. Additionally, secondary crushers are usually impact crushers which produce aggregates of good quality (than jaw crushers) with less attached mortar (Etxeberria et al., 2007). Moreover, along with crushers, each stage has some screens to sort/separate aggregates of interest and mentioned contaminants.
Fractal dimension of crushing products: effects of feed size distribution and feed rate
Published in Particulate Science and Technology, 2021
The size distribution of the particles yielded by crushing may be influenced by several parameters such as feed rate, crushing mechanism, morphology of the ore pieces, feed size distribution, and so on. Any change in each of these parameters, and depending on the behavior of the ore in the crushing stages, the particle size distribution would exhibit different distributions. Each crusher operates with a dominant mechanism (such as compression, impact, shear, and abrasion). In the present study, the three crushers had the same mechanism, and the compressive force was the dominant force for crushing the ore. Here, the selected feed size distribution and feed rates were investigated as the main establishing parameters of the crushing operations. The maximum feeding capacity was 3.5 kg/min for the three laboratory crushers. To investigate the effect of feed rates on the performance of these three crushers, the input feed was carried out at permitted capacities (1, 1.5, 2, 2.5, 3, and 3.5 kg/min). In addition, the effect of feed rate at unpermitted capacities was investigate by testing the feed rates of 4 and 4.5 kg/min. All the jaw, cone, and roll crushers were successively operated in the open-circuit modes and particle size distribution (PSD) was determined for each crusher. The effect of the selected feed size distribution was investigated on the PSD of the products. The weight and size distribution composition of the feeds to the jaw, cone, and roll crushers are presented in Tables 3–5, respectively.
A multi-objective model for fleet allocation schedule in open-pit mines considering the impact of prioritising objectives on transportation system performance
Published in International Journal of Mining, Reclamation and Environment, 2021
Mehrnaz Mohtasham, Hossein Mirzaei-Nasirabad, Hooman Askari-Nasab, Behrooz Alizadeh
The case study is the Sungun open-pit mine, located in Varzaqan, Tabriz province, Iran. The mine is a copper mine with nine mining faces where loaders are distributed in these faces between the benches at levels 1912.5–2312.5 m. Four of these mining faces (mining face 1, 2, 3, and 4) are located in the valuable mineral area and the others (mining face 5, 6, 7, 8, and 9) are in the waste area. The average grade of copper at mining faces 1, 2, 3, and 4 are 1.42%, 0.74%, 0.92%, and 0.39%, respectively. The upper limit of copper grade is 0.78% and the lower limit of copper is 0.68%. To control the quality of copper at the right level, the desired grade of copper is considered 0.73%. There are three different destinations in the mine: one crusher ( and three waste dumps (. The ore material is unloaded into bins of the desired capacity of 18,000 tons per shift that feed the copper to the crusher and waste is unloaded into waste dumps without capacity limitations. The maximum and minimum capacity for the crusher is 20,000 and 15,000 tons, respectively. The mine is active in three 7-hour shifts throughout each normal day. The current mine policy used to address the truck allocation plan is the fixed allocation plan. The different major equipment in the mine is trucks and loaders. A heterogeneous fleet of 35 trucks is used in the haulage. The fleet of trucks is made up of 25 Komatsu HD325 trucks with a nominal capacity of 32 tons and 10 Komatsu HD785 trucks with a nominal capacity of 100 tons. So, two types of trucks are available in the given shift. The mixed fleet of loaders consists of five different types of loaders with 3 Komatsu 600 and 1 New Holland 270 loaders specifically for ore and 1 Komatsu 800, 3 Caterpillar 988, and 1 Komatsu 1250 loaders only for waste mining based on the mine allocation strategy. The idle, empty, and loaded fuel consumption for Komatsu HD325 trucks are considered to be 10 litres, 22 litres, and 40 litres per hour and for Komatsu HD785 trucks are 22 litres, 44 litres, 78 litres per hour, respectively. As mentioned earlier, the capacity of trucks should be compatible to work with the bucket capacity of loaders considering the density and size of materials and operational conditions. The trucks and loaders used are matched in terms of height and passes. In this paper, a chronograph instrument was used to record each truck’s cycle time. All the relevant parameters related to the truck cycle times are given in Tables 2–4. The MILGP model presented is supposed to work with the short-term production plan information of the mine.