Recovery of ‘Nsutite’ from Tailings Material of Ghana Manganese Company (GMC) Limited Mine, Nsuta

An investigation was conducted for the enrichment of manganese oxide tailings generated by a spiral concentration plant at Ghana Manganese Company (GMC) Limited, Nsuta. The work involved mineralogical and particle size characterisation, grav-ity and magnetic separation techniques. Analytical methods used include; X-Ray Fluorescence and Atomic Absorption Spectro-photometry. The material composed of 9.01% Al2O3, 27.43 %SiO2, 19.28% MnO2 and 9.86% Fe2O3, while other oxides ranged between 1.55 and 0.04%. By treating the distinct size fractions, it was discovered that the most efficient method was heavy medium separation at a bath density of 2.96 having an overall recovery of 51.18%. Enrichment ratios of 1.28, 0.98 and 0.91 were obtained in order of heavy medium separation, magnetic separation and shaking table. The highest grade obtained was 38.25% Mn which qualifies the concentrate as medium grade material in the manganese market

Bore and Well Water Quality Studies in The Tarkwa-Nsuaem Municipality and Prestea-Huni-Valley District, SW Ghana

The quality of bore and well water within the Tarkwa-Nsuaem Municipality and Prestea-Huni-Valley District has been studied. The major cationic pollutants with concentrations above the WHO standards were iron, molybdenum, lead, mercury and manganese. High nitrate levels were found in boreholes at Akoon and Brenu Akyim which are communities close to active large scale mines where nitrates are major constituents of the explosives utilised. The study revealed that due to high microbial contamination, wells and boreholes at Tarkwa Community Centre, GAG Mile 7, Teberebie Roadside, Samahu Quarters, Dumasi, Abekoase, and Prestea Anyinam will require shock chlorination. Such a step can potentially reduce the numerous domestic water related sicknesses recorded in the investigation. Hydrochemical modelling using PHREEQC software indicated that some minerals had high saturation indices with the highest being goethite, hematite and ferric hydroxide at 7.38, 16.78 and 1.38 respectively within a borehole at Dumasi. The relatively high saturation indices of the iron oxides and hydroxides in the Dumasi samples explain the reddish brown precipitate formed when the samples are allowed to stand for a while. The results demonstrate that geological, mining and non-mining community related activities contribute to the water quality within the study area

Economic Viability of the Use of Local Pseudo-Oils for Drilling Fluid Formulation

The initial cost of formulating Synthetic Base Muds (SBM) compared to conventional Oil Base Muds (OBM) may be doubled but after considering the cost of containment, hauling, and disposal of OBM after use, the cost of using SBM becomes relatively cheaper. The formulation and disposal options (onshore and offshore) and the cost benefit of using seven local antioxidated pseudo-oils (vegetable esters) SBM compared to commercial OBM at an average offshore and onshore temperature operations were simulated in this work using API standard performance benchmarks. The average cost percent of savings on the use of the seven local vegetable oils over the use of commercial synthetic base fluid offshore and onshore were 48.32% and 56.30% respectively. Thus the use of local ester oils for drilling fluids formulation are more economical compared to currently imported oil based drilling fluids. The cultivation and production of these local pseudo-oils are on the increase guaranteeing its adoption and application to be very sustainable.Keywords: Antioxidants, Disposals, Economics, Esters, Formulation

Utilization of Microwave Energy in the Calcination and Agglomeration of Nsuta Manganese Carbonate Ore

The application of microwave energy in the calcination and agglomeration of manganese carbonate ore from Nsuta, Ghana, has been investigated. The real and imaginary permittivities, which may be used to determine a substance's response to microwave heating, were measured and the permittivities of both the ore and calcine were relatively low at low temperatures. Beyond 600oC, both the real and imaginary permittivities increased more rapidly with that of the calcine reaching relatively high values. The degree of microwave absorption and thus the temperature attained by the samples during microwave heating increased with sample mass, processing time and incident microwave power. Processing temperatures of over 1500oC could be attained under optimum microwave coupling. Calcination and agglomeration tests were performed and the calcine obtained readily absorbed microwaves. The tumbler index of the agglomerated material was 90 and the average crushing strength was 2550 KN. Ghana Mining Journal Vol. 9 2007: pp. 54-6

The use of the High-Temperature Gas-Balance (HTGB) for thermogravimetric measurements

Several methods are established in thermal analysis to investigate phase formation, phase transition, and decomposition reactions. The analysis of phase equilibria with volatile components is particularly feasible by using standard method of thermogravimetry. Hardly any investigations of phase formation reactions are possible to realize if one of the components is lost by vaporization. By using the 'High-Temperature Gas-Balance' (HTGB), the vapor phase is enclosed in a silica ampoule and thus forms an equilibrium gas phase in permanent contact with the solid phase. The measurement signal Δ m is caused by change of the leverage of the horizontal balance support during evaporation and condensation. The application of the HTGB allows the analysis of solid-gas equilibria in the working range from 0.01 till 15 bar at temperatures up to 1,100 °C. The first comparison of evaporation reactions determined by standard thermogravimetric analyses and by measurements using the HTGB is given for the inorganic systems: P, As, SeO, PtI, and Hg/I