Underground mining machines - Mobile extracting machines at the face - Safety requirements for shearer loaders and plough systems

An important task in the technological process of a mining enterprise is preparatory mine working performance, as effective operation of an entire mining complex depends on rate and quality of drilling. Therefore, the main factor affecting the performance of the process of underground mining is the correspondence of design and operating parameters of the working bodies of tunnelling machines to mining and geological conditions. The underground mining operations showed that rocks with a strength f ≤ 10 and high abrasiveness are to be destroyed with disc tools, providing higher strength, wear-resistant parameter and low dust formation in comparison with cutters. The usage of disk tools on the working bodies of tunnelling machines of selective action is a poorly studied task and requires special research of the questions of destruction, crushing and loading of rocks at reverse working modes. It has been established that researches aimed at design development of an attachment point of a disk tool for arrow-type working bodies of a tunnelling machines is an urgent scientific task. The original technical solutions for the design of the attachment points of disc and cutter tools are proposed to improve the processes of cutting of working bodies in the face massif, dust suppression, sealing and mounting-dismounting operations at the operation of shearers and tunnelling machines.

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Local dynamics exacerbate Africa copper sector woes

Emerald Expert Briefings ◽

10.1108/oxan-db213429 ◽

2016 ◽

Keyword(s):

Sub Saharan Africa ◽

Copper Production ◽

Content Type ◽

Safety Requirements ◽

The Face ◽

Sub Saharan ◽

The Government ◽

Slight Rise ◽

Current Slump ◽

Unemployment Problem

Subject Outlook for the copper sector in sub-Saharan Africa. Significance Africa's copper production is forecast to be marginally lower in 2016 at 1.823 million tonnes, compared to 1.895 million tonnes in 2015. This is due to production cutbacks implemented in the face of continued weakness in international -- especially Chinese -- demand. A slight rise in prices earlier in the year was not sustained, dampening the economic prospects for major exporting countries. Impacts The deaths of several miners at a Glencore mine in Zambia may push the government to enforce tougher safety requirements. Miners are unlikely to restore all the jobs shed during the current slump, extending the region's unemployment problem. Divisions within the Congolese opposition on whether to negotiate with Kabila on the delayed polls will exacerbate political tensions.

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Innovative Techniques in Underground Mining for the Prevention of Gas Dynamic Phenomena

Energies ◽

10.3390/en14165205 ◽

2021 ◽

Vol 14 (16) ◽

pp. 5205

Author(s):

Martina-Inmaculada Álvarez-Fernández ◽

María-Belén Prendes-Gero ◽

Juan-Carlos Peñas-Espinosa ◽

Celestino González-Nicieza

Keyword(s):

Underground Mining ◽

Initial Permeability ◽

Mining Operations ◽

Loss Of Life ◽

Gas Dynamic ◽

Innovative Method ◽

Rigorous Research ◽

The Face ◽

Innovative Techniques ◽

Dynamic Phenomena

In the last decades, rigorous research has been carried out with the end of understanding the gas dynamic phenomenon and although different preventive techniques have been employed, even today there are numerous accidents even with the loss of life. This work analyses an alternative and innovative method of fracturing and degassing coal, by generating CO2 with a pyrotechnic device called PYROC (Pyrotechnic Break Cartridges). Medium-scale tests of generation of CO2 into coal samples are carried out and their effect is analysed comparing the initial and final permeabilities of the coal samples once the generation of CO2 has finished. These permeabilities are calculated by injecting methane. Besides, the influence of different parameters as the length of the boreholes, the pressure of the gas or the initial permeability of the coal have been analysed with a numerical simulation of one face of one of the sublevels of a mine. The results show that the method increases the safety in mining operations because it fractures and degasses the coal, increases the permeability of the coal in the borehole of injection from 9.5 mD to 31 mD, decreases the methane gas pressure below pre-detonation levels for 1 min, achieves decompressed lengths between 8 and 10 m ahead of the face with pressures of injection of 50 MPa, relaxes the total length of the borehole for initial coal permeability values equal to or greater than 0.002 mD, and allows to work with low permeable coals with high induced stresses and high methane concentrations.

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Deformation Characteristics of a Technological Pillar in the Chamber-Pillar Mining System/Charakterystyka Deformacyjna Filara Technologicznego W Komorowo-Filarowym Systemie Eksploatacji

Archives of Mining Sciences ◽

10.2478/amsc-2014-0023 ◽

2014 ◽

Vol 59 (2) ◽

pp. 323-335

Author(s):

Wiesław Grzebyk ◽

Lech Stolecki

Keyword(s):

Underground Mining ◽

Measurement Techniques ◽

Measurement Data ◽

Deformation Characteristics ◽

Mining System ◽

The Face ◽

Pillar Mining ◽

In Situ Observations ◽

Mining Works

Abstract The article presents the suitability of the new measurement techniques for monitoring deformations of the technological pillars and fragments of the face in underground mining. The conducted observations concerned the mined pillar located in the lead of mining field G-3/4 of Rudna mine (mine belongs to KGHM Polska Miedź S.A.) in a situation of constant progress of mining works in its direction. The observations conducted underground provided results demonstrating the suitability of the applied observation techniques in this area. The obtained measurement data directly describe the volumetric changes which form the basis for assessing the stress of the rock formation. This issue is well recognised based on the tests on rock samples. Further studies should concern the transfer of these experiences to the results of in situ observations.

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VERDICT: A Language and Framework for Engineering Cyber Resilient and Safe System

Systems ◽

10.3390/systems9010018 ◽

2021 ◽

Vol 9 (1) ◽

pp. 18

Author(s):

Baoluo Meng ◽

Daniel Larraz ◽

Kit Siu ◽

Abha Moitra ◽

John Interrante ◽

...

Keyword(s):

Critical Infrastructure ◽

Cyber Physical Systems ◽

Design Model ◽

Physical Systems ◽

Architectural Analysis ◽

Analysis And Design ◽

Safety Requirements ◽

Analysis And Synthesis ◽

The Face ◽

Implementation Costs

The ever-increasing complexity of cyber-physical systems is driving the need for assurance of critical infrastructure and embedded systems. However, traditional methods to secure cyber-physical systems—e.g., using cyber best practices, adapting mechanisms from information technology systems, and penetration testing followed by patching—are becoming ineffective. This paper describes, in detail, Verification Evidence and Resilient Design In anticipation of Cybersecurity Threats (VERDICT), a language and framework to address cyber resiliency. When we use the term resiliency, we mean hardening a system such that it anticipates and withstands attacks. VERDICT analyzes a system in the face of cyber threats and recommends design improvements that can be applied early in the system engineering process. This is done in two steps: (1) Analyzing at the system architectural level, with respect to cyber and safety requirements and (2) by analyzing at the component behavioral level, with respect to a set of cyber-resiliency properties. The framework consists of three parts: (1) Model-Based Architectural Analysis and Synthesis (MBAAS); (2) Assurance Case Fragments Generation (ACFG); and (3) Cyber Resiliency Verifier (CRV). The VERDICT language is an Architecture Analysis and Design Language (AADL) annex for modeling the safety and security aspects of a system’s architecture. MBAAS performs probabilistic analyses, suggests defenses to mitigate attacks, and generates attack-defense trees and fault trees as evidence of resiliency and safety. It can also synthesize optimal defense solutions—with respect to implementation costs. In addition, ACFG assembles MBAAS evidence into goal structuring notation for certification purposes. CRV analyzes behavioral aspects of the system (i.e., the design model)—modeled using the Assume-Guarantee Reasoning Environment (AGREE) annex and checked against cyber resiliency properties using the Kind 2 model checker. When a property is proved or disproved, a minimal set of vital system components responsible for the proof/disproof are identified. CRV also provides rich and localized diagnostics so the user can quickly identify problems and fix the design model. This paper describes the VERDICT language and each part of the framework in detail and includes a case study to demonstrate the effectiveness of VERDICT—in this case, a delivery drone.

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