Assessment of the Loss of Gold to the Tailing Dam: A Case Study on Meli Gold Plant, Northwestern Tigray, Ethiopia.
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Date
2020-09-08
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Addis Ababa University
Abstract
This study is designed to evaluate and calculate a possible gold loss by metallurgic operation of meli gold plant which is located in northwestern Tigray region, northern Ethiopia. To understand the problem systematic samples has been carried out from tailing dam. Geochemical analysis in support with secondary data review has been done.
From geochemical data analysis of samples, concentration of gold in the tailing dam was found to be significant amount. The gold grade in the tailing dam falls within the range of 1.14 to 0.34g/t with an average grade of 0.61g/t. This indicates loss of gold in the tailing dam. As evidenced from the geochemical results, there exists a clear gold grade decrement as it moves from outlet to inlet.
One of the possible cause for gold loss to the tailing dam is the presence of base metals (Cu, Ni, Zn..). They affect the rate of gold dissolution because they consume both cyanide and the dissolved oxygen and forming stable complexes with cyanide and retarding gold cyanidation. In addition to these the lime proportion and pH regulation problems affect the gold recovery and leads to loss of gold. For mitigating gold loss for ore containing soluble copper, multi stage leaching, Ammonia-cyanide mixtures, treating by non-cyanide leaches such as thiorea leaching can be employed. Moreover, EMD needs to use 60-75% of particle size percentage range. In addition to these proper maintenance of the lime feeder should have to be done.
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Assessment, Loss of Gold, Tailing Dam, Case Study on Meli Gold Plant, Northwestern Tigray, Ethiopia