Internationalisation of Artisanal and Small Scale Mining in Ghana: Opportunities and Challenges

The last few years have witnessed internationalisation of small scale mining in Ghana. The entry of migrant artisanal miners has brought losers and winners in the subsector, creating myriad of socio-political problems. However, official attempts to curb it have exacerbated the systemic problem of mineral governance. This paper analyses the emerging challenges and opportunities posed by the entrance of migrant miners into the country with insights into assumptions on resources and conflicts. It takes a closer look at the causes, effects and dynamics of confrontation and collaboration between migrant artisanal and small scale miners and their counterparts in the host nation. It argues that the current governance system of small scale mining based on national control over exploitation is anachronic and not well adapted to competitive, sustainable and fair management of mineral resources. In addition, it proposes a sustainable partnership to harness complimentary skills in order to avoid deepening the resources conflicts which have plagued the mining districts.  Keywords: Internationalisation, Artisanal, Small Scale Mining, Sustainabilit

Determination of performance evaluation of Mobile Manufacturing Units (MMUs) for surface mines: an OEE approach

For the measurement of overall equipment effectiveness, it is necessary to determine the magnitude of the types of production losses in order to plan activities and allocate resources effectively. The application of Overall Equipment Effectiveness (OEE) in Mobile Manufacturing Units for mining operations have not been duly adopted. There is the need to do the assessment of maintenance performance indices like availability and utilisation for improvement in productivity. This paper seeks to determine the maintenance performance indices like availability and utilisation of Mobile Manufacturing Units (MMUs) of African Explosives Limited (AEL) operations at Goldfields Ghana Limited, Damang. It was determined that the availability and utilisation were 93.55% and 30.61% respectively. The results obtained can contribute to the knowledge about the solution for improvement in scheduling of mine operations and the efficient monitoring of controllable factors that enhance maximum availability and utilisation of MMUs.Keywords: Explosive, equipment, availability, utilization, maintenance, manufacturin

Effect of Riffle Height and Spacing of a Sluice Board on Placer Gold Recovery

Sluicing is the preferred mineral processing technique for the treatment of placer gold-bearing alluvium for small scale and artisanal miners in Ghana because sluice board is perceived to be the most cost effective device. However, there are differences in approaches from design to operation.  In this work, about 50 kg of ore was obtained from “Peace School” small scale mining site near the University of Mines and Technology, Tarkwa. It was processed to determine the effects of riffle height and spacing on gold recovery. It was confirmed that, in order to trap a greater percentage of gold particles, the height of the riffle ought to be higher than the suspension height of the gold. The suspension heights of the gold particles of the various operational regimes of the sluice board at superficial velocities of 0.5 m/s, 1.0 m/s, 1.5 m/s and 2.0 m/ were   0.9 cm, 1.2 cm, 1.5 cm and 2.9 cm respectively. Analysis of concentrates showed that, 85.4% of gold was recovered during sluicing at approximately 1.0 cm riffle height.  The lowest recovery was recorded at 0.5 cm riffle height. Gold recovery was also affected by riffles spacing.  For the indicated speeds and the riffle heights the necessary spacing should not be more than 20 cm. The peak recovery was obtained at a riffle height of 1.0 cm but dropped after 20.0 cm spacing. Keywords: Sluice Board, Riffle Height, Gold, Rifle Spacing

A Comparative Analysis of Rock Fragmentation using Blast Prediction Results

This work presents prediction and optimisation of controllable parameters of drilling and blasting currently used at the Fobinso Pit of Perseus Mining Ghana Limited (PMGL). The mine faces challenges with blast particle sizes produced after primary blasting. The presence of boulders requires secondary fragmentation to further reduce the broken materials to the acceptable sizes, thereby increasing the cost of production. The mechanical properties of the rocks were determined using Protodyakonov Rock Strength Index. The drill and blast parameters were estimated using the Konya and Walter (1990), Principle of Proportionality, and Instituto Geologo Minero de España (IGME) model developed in 1987. The Modified Kuz-Ram model was used to predict and analyse the results of blasting based on the parameters such as spacing, burden, drillhole diameter, charge density, charge per hole, charge length, and powder factor. A comparative analysis of the predicted size distributions of the various models using diameters of 65 mm and 110 mm revealed no significant differences between the size fractions. The Principle of Proportionality produced the best technical and economic indices for blasting. Keywords: Fragmentation, Drilling Parameters, Primary Blasting, Models, Secondary Blastin

Slope angle estimation of Amoanda East Pit of Abosso Gold Fields, Ghana

This paper determines the possible modes of slope failure, and the effect of increasing the slope angle of the Amoanda East Pit Wall of Abosso Gold Fields Limited, Damang Mine by 5° and 10° from 70 o because the designed slope angle (70° ) will increase ore losses at Amoanda East. The methods employed include field geotechnical mapping of the slope face, and kinematic analysis using DIPS 6.0 software to analyse the modes of failures. Based on the kinematic analysis conducted using the slope angle per design (70° ), it was found that the percentage of toppling, planar and wedge failures obtained were 20.05%, 5.41% and 0% respectively. Also, when the slope angle of Amoanda East Pit Wall was increased by 5 o (75°) and 10° (80° ), there was percentage increase in toppling and planar failures of (0.12 and 0.99) % and (2.59 and 4.18) % respectively, with no increment in wedge failure. Hence there is the possibility of planar and toppling failure with no wedge failure occurring at the Amoanda East. It is therefore recommended that, since the percentage increment in toppling and wedge were not significant when the slope angle was increased, the mine should continue to increase the slope angle by 5° and 10°from 70° .Keywords: Slope, Toppling, Planar, Failures, Open Pit, Kinemati

Slope stability analysis of Nkran Pit at Asanko Gold Mine, Ghana

The West Wall of Nkran Pit Mine is vulnerable to slope instability, mostly due to mining activities. Detailed failure analysis of the discontinuity data of the selected slope was performed using the Dips (6.0) software. The study has shown the likelihood of planar failure, wedge failure, flexural toppling failure and direct toppling failure occurring per the slope angle design of 70°. When the slope angle was increased by 5° and 10°, there were percentage increases in planar, wedge, flexural toppling and direct toppling failure of (1.86 and 7.45)%, (1.23 and 2.81)%, (0.62 and 0.62)% and (0.60 and 1.70)% respectively. It has been recommended that flattening or reducing slope angle could be done as it reduces the weight of material which in turn improves the stability of the slope and also controlled blasting should be employed to minimise excessive damage to the walls.Keywords: Slope, Stability, Toppling, Minin

Comparative analyses of the return on investment of 2013 and 2015 mineral policy reforms in Burkina Faso

This paper evaluates the effects of the changes in Burkina Faso’s mineral policies of 2013 and 2015 and their economic attractiveness using the Natougou Project as case study. Cash flow analyses shows a higher NPV of US $93,817,833.84 and an IRR of 44.67$ 321,488,366.61 will accrue to the government for 2015 Mining Code as against US$ 245,442,053.07 for the 2003 Mining Code.Keywords: Mining Code, investment, physical policies, dividends, sensitivity analysis, government and projec

Waste Dump Closure and Cost Estimates at AngloGold Ashanti Iduapriem

AngloGold Ashanti Iduapriem Mine is a surface gold mine which produces waste rock in its operations. The waste rock forms waste dumps which grow over the years, and will ultimately need to be closed down when they are filled to the maximum capacity. The mine has closure plans for the waste dumps and the closure activity will incur cost. This research was carried out to study the waste dump reclamation and closure plan for the Ajopa waste dump, and estimate the associated cost. The aim of the closure is to establish a permanent stable landscape that is environmentally compatible with surrounding undisturbed land. The waste dump will be closed with a progressive rehabilitation technique. The key activities involved in the reclamation plan, which are earthworks, capping and revegetation were identified and studied into detail. The reclamation plan and cost estimates were prepared on the basis that AngloGold Ashanti Iduapriem Mine would contract with a third-party contractor to fully execute the required closure and reclamation activities. The cost was then estimated using price quotes from vendors or contractors located around the mining area. Results showed that waste dump closure and reclamation programme for Iduapriem Mine are consistent with Ghana Mining and Environmental guidelines. The total closure and reclamation cost was estimated to be US$ 581 488.18. Since any delay in the closure and reclamation could incur additional cost, it was advised that the mine should execute the closure and reclamation plan without delay. Keywords: Waste Dump, Reclamation, Revegetation, Estimate

Health risk assessment model for lead contaminated soil in Bagega Community, Nigeria

The study developed health risk assessment model for lead contaminated soil in Bagega community using United States Environmental Protection Agency (US EPA) and Canadian Standards Association (CAS) standard procedures. Questionnaires were used to investigate the background causes and exposure pathways of lead contaminated soil. Soil samples were collected at five different sites and cancer health risk values were estimated using equations proposed by US EPA. The results show that 84.0 % of the respondents agreed that the causes of lead poisoning in the study area were due to the activities of artisanal gold miners. The major exposure pathways to lead contaminated soil are ingestion, dermal contact and inhalation while the soil ingestion generates high cancer risk, dermal contact generates low cancer risk and that of inhalation was insignificant when compared with 1.00E-06 (mg/kg/day) WHO cancer risk standard. The mean cancer health risk value for combined exposure pathway is ranged from 1.49E-03 mg/kg/day to 5.99E-03 mg/kg/day. The study established that lead contaminated soil posed cancer health risk to the people of the study area

Trace elements contamination of soils around gold mine tailings dams at Obuasi, Ghana

This study investigated the issue of tailings dams as a potential source of trace elements contamination in soils at the Obuasi gold mine in Ghana. Soil samples taken from depths of up to 12 cm and within a radius of 400 m from the tailings dams (active and recommissioned), were analysed for As, Cu, Pb and Zn using atomic absorption spectrometry. Average concentrations of As, Cu, Pb and Zn in soils around the active tailings dams were respectively 581±130, 39.64 ± 3.02, 24.22 ± 2.62 and 72.64 ± 8.01 mg/kg. Soils in the vicinity of the decommissioned tailings dam registered increased values - 1711 ± 172, 71.44 ± 5.27, 38.67 ± 3.59 and 168.1 ± 36.2 mg/kg for As, Cu, Pb and Zn respectively. Both types of tailings dams impacted adjoining soils with greater concentrations of the trace elements when compared to undisturbed control soils. Arsenic was above the Netherlands intervention value of 55 mg/kg dry weight, even in control soils. The following trend of accumulation was observed in the soils: As>Zn>Cu>Pb. Improved tailings management strategies, among other factors, might have influenced the reduced level of trace elements contamination at the active tailings dams’ site