Ore Dilution Estimation Model in Tanzania Southern Highland Zone: A Case of New Luika Gold Mine

Mtaita Charles Mtoni

doi:10.11648/j.ijsqa.20180401.12

Abstract

This paper brings about understanding of the effect of ore dilution to the economics of mine and reveals that, mining ore dilution is one among factors affecting the economy of mining projects. Dilution factor varies within a single mine for different benches and zones due to changes seen in grade distribution and shape of ore body, also varies based on commodity price obtained. It was necessary to make sure that these variations were taken into account during designing or evaluating a mine. The study identified suitable methods that are supposed to be used for estimation of ore dilution level which are: Geological review method, loading and haulage methods. By checking the number of dilution from the data, the percentage of dilution, the total tons of ore and total tons of waste was computed by the formula of dilution, the computed average dilution estimation was found to be 64% which was then used in determination of an increase level of ore dilution by comparing obtained results to the standards ore dilution used by the company. Normally the company estimated 20% up to 23% as standard ore dilution which brings about the average of 21.5% standard ore dilution. Upon considering the factor of standard planned ore dilution in the Company, the finding proved that there is an increase by 42.5% ore dilution during operation each day. Upon considering factors concerned with the process of comminuting, the results shows that grade from grade control is 4.73 g/t and grade of the final product is 3.95 g/t and the grade difference is 0.78 g/t where by factors like, leakage, slurry overflow, some other chemical agents in the CIL tanks that take place in the process like (CIL) Carbon In Leach process, crushing and grinding are taking into consideration. The study shows that, the dilution per hour in a given bench is above standard planned ore dilution. By checking the line graph from the findings it shows the dilution per hour in a given bench is higher than standard planned by the company which is 29%.

Highlights

Ore dilution is well defined as waste materials that are not separated from the ore during the operation and are mined with ore [2]
The New Luika Gold Mine (NLGM) which is operated by Shanta Mine Company Limited (SMCL’s) and located within the Songwe district in Songwe Administrative Region is experiencing the problem of high level of ore dilution compared to the standard estimated ones
Mtaita Charles Mtoni: Ore Dilution Estimation Model in Tanzania Southern Highland Zone: A Case of New Luika Gold Mine changes in other factors that on the long term lower the general value of the project

Summary

Introduction

Ore dilution is well defined as waste materials that are not separated from the ore during the operation and are mined with ore [2]. Dilution tends to increase tonnage and reduce grade of ore during and after mining operation [4]. While the best procedures are done to identify and calculate all the other cost items of a project, no matter how small, it is common to make general assumptions about dilution instead of quantifying it. Due to insufficient budget, time for studies and lack of a well-defined methodology, the company tends to make general assumption instead of quantifying ore dilution. A Case of New Luika Gold Mine changes in other factors that on the long term lower the general value of the project. It draws out the mine life by diminishing mill’s effective limit. Abnormal state and uncontrolled dilution may at last nullify the point of expanding production rates [7]

Methods

Analysis

I I II I I I I II 13

Geological Review

Conclusion