Open Access. Powered by Scholars. Published by Universities.®

Mining Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 3 of 3

Full-Text Articles in Mining Engineering

Predictive Modeling Of Dc Arc Flash In 125 Volt System, Austin Cody Gaunce Jan 2019

Predictive Modeling Of Dc Arc Flash In 125 Volt System, Austin Cody Gaunce

Theses and Dissertations--Mining Engineering

Arc flash is one of the two primary hazards encountered by workers near electrical equipment. Most applications where arc flash may be encountered are alternating current (AC) electrical systems. However, direct current (DC) electrical systems are becoming increasingly prevalent with industries implementing more renewable energy sources and energy storage devices. Little research has been performed with respect to arc flash hazards posed by DC electrical systems, particularly energy storage devices. Furthermore, current standards for performing arc flash calculations do not provide sufficient guidance when working in DC applications. IEEE 1584-2002 does not provide recommendations for DC electrical systems. NFPA 70E ...


Operation And Process Control Development For A Pilot-Scale Leaching And Solvent Extraction Circuit Recovering Rare Earth Elements From Coal-Based Sources, Douglas Kweku Addo Jan 2019

Operation And Process Control Development For A Pilot-Scale Leaching And Solvent Extraction Circuit Recovering Rare Earth Elements From Coal-Based Sources, Douglas Kweku Addo

Theses and Dissertations--Mining Engineering

The US Department of Energy in 2010 has identified several rare earth elements as critical materials to enable clean technologies. As part of ongoing research in REEs (rare earth elements) recovery from coal sources, the University of Kentucky has designed, developed and is demonstrating a ΒΌ ton/hour pilot-scale processing plant to produce high-grade REEs from coal sources. Due to the need to control critical variables (e.g. pH, tank level, etc.), process control is required. To ensure adequate process control, a study was conducted on leaching and solvent extraction control to evaluate the potential of achieving low-cost REE recovery ...


Active Current Injection Method For Limiting Ground Fault Current Harmonics In Underground Coal Mines, Yigong Zhang Jan 2014

Active Current Injection Method For Limiting Ground Fault Current Harmonics In Underground Coal Mines, Yigong Zhang

Theses and Dissertations--Mining Engineering

Current practice in U.S. underground coal mine high-voltage distribution systems is to attempt to limit ground fault current to 25 Amperes and de-energize the circuit at 10 Amperes. However, the significant amount of system capacitance due to the use of shielded cables can cause ground fault current to be two or three times the intended ground fault limit. Consequently, this practice can cause several issues such as ground fault currents significantly exceeding the neutral grounding resistor current limit, loss of relay selectivity in the distribution system, and transient overvoltages in certain ground fault situations. These issues are solved to ...