Modern Mining January 2021

TIN

maintaining steady state production, while exploring opportunities for further optimisation and expansion of the operation. These opportunities include a mod- ular expansion of the plant throughput, and potential production of a by-product in the form of a tantalum concentrate. “The work ahead to remodel areas of the plant will focus on optimising throughputs and recover- ies. Given the modular design of the plant we can increase these throughputs and recoveries incre- mentally. Due to the size of the ore body, and the gravity-based nature of the plant, economies of scale come into play as we will become more economical the more concentrate we produce,” explains Viljoen. The company is conducting test work to investigate the feasibility of separating the more magnetically susceptible tantalum minerals from the tin concentrate. “We are encouraged by early test work results which indicate the potential of simple

recoveries in the processing plant. The particle size distribution of the plant feed proved to be finer than initial design parameters derived from test work. This resulted in a bottleneck in the fines dewatering section of the plant which was addressed through increasing the capacity of the slimes and grits dewa- tering circuits. Debottlenecking of the processing plant focused on the dewatering of the grits tailings (less than 630 microns), dewatering of the slimes tailings (less than 45 microns) and expanding the feed capacity to the spiral plant. “To counter high wear rates due to the abrasive- ness of the ore material we had to look at abrasion resistant materials, optimisation of flow lines and enhanced maintenance planning. Other initiatives included improved process control and retraining of operators,” says Viljoen. Looking ahead, AfriTin will now focus on

The company is conducting test work to investigate the feasibility of magnetically separating tantalum minerals from the tin concentrate.

Monthly performance of the Uis Phase 1 pilot plant during 2020

2020

Description

Units

Jan Feb Mar

Apr *

May Jun Jul

Aug Sep Oct

Nov

Plant Availability

% 59% 60% 64% 59% 65% 69% 73% 72% 74% 81% 83% % 58% 66% 68% 54% 70% 76% 88% 81% 85% 85% 87%

Top projects Plant Utilisation

Plant Processing Rate tph 45 51

52 41

48 49 65 70 69 73

74

Ore Processed Tin Concentrate Tin Contained in Concentrate

t 11 420 14 043 16 866 9 618 16 217 18 551 31 324 30 872 30 831 36 796 38 211

t t

11,4 11

12,3 11,1 8,4 7,7

11,2 19,7 35,3 37,5 39 48,5 63,9 7,2 12,6 22,7 25,6 27,5 32,2 41,6

7,4

7,1

* Operations curtailed due to COVID-19 lockdown regulations

16  MODERN MINING  January 2021