Mimosa

Mimosa is a shallow, mechanised PGM and base metal mining operation located in the Wedza sub-chamber of the Great Dyke of Zimbabwe, some 32km west of Zvishavane, a major mining centre situated 340km south-west of Harare, the capital city of Zimbabwe.

Statistics as at 31 December 2022

Life of mine

2034

Production 4E PGM

115,534oz

All-in sustaining cost

US$1,150/oz

Jointly owned

50/50

with Implats

The Mimosa property has four mineralised areas separated by major faults and erosional surfaces namely: North Hill, South Hill, Far South Hill and the Mtshingwe Block. The Mimosa mine is an underground operation on the South Hill ore deposit, consisting of two shafts, namely the Blore Shaft and the Wedza Shaft. At Mimosa, focus is on developing the Mtshingwe Shaft and further evaluating the Mtshingwe Block.

As at 31 December 2022 and on a 50% attributable basis, Mimosa had 4E PGM Mineral Reserves of 3.2Moz and 4E PGM Mineral Resources of 7.0Moz.

A closer look

Property and infrastructure

Mimosa is an established mechanised, bord and pillar mining operation, with all the facilities and equipment to mine and produce precious and base metals concentrate.

There are two decline shafts, and a small vertical shaft at 26 Level South which is equipped for hoisting people to surface in case of an emergency. Underground infrastructure includes an ore bunker, main and satellite workshops, pump stations, strike and dip conveyors as well as the main conveyor in Blore shaft. Blore shaft has an operational capacity of 280ktpm. A fleet of trackless mining machinery (TMM) to enable the mechanised bord-and-pillar operation.

The fleet of TMM equipment is serviced and repaired in the main underground workshop, which is adequately equipped for the purpose. Surface Infrastructure includes an ore stockpile, concentrator plant, garage, workshops, dirty water settling ponds, service and potable water storage tanks, a clinic and housing for selected essential staff.

The Mimosa concentrator has an operational capacity of ~233 ktpm. Concentrates are transported by road to South Africa for smelting and refining at the Impala Platinum facilities.

Mineral title

The Mimosa mining right is covered by a mining lease covering an area of 65.94km². The mining lease, Lease No 24, was granted to Mimosa Mines (Pvt) Ltd on 5 September 1996, giving it the exclusive mining rights for PGMs and base metals within the vertical limits of its boundary. As per Zimbabwean law, the mining right does not expire under the provisor that annual renewal fees are up to date.

Mimosa also holds the following valid claims ; Fifty (50) KV Platinum Claims (4.84km² – referred to as the Wedza West), Thirty-seven (37) SR Platinum Claims (3.70km²), Seven (7) Chrome Claims (1.75km²), and a 0.30km² block pegged in 2020 over the Mtshingwe Fault block.

Tailings deposition and capacity

Tailings Storage Facilities are detailed below

Mimosa TSF3 is fed from Mimosa plant at 229ktpm (life of TSF until 2024 at current deposition rate)
Mimosa TSF4 is currently under construction (life of TSF until 2044 at 233ktpm deposition rate)

The Mimosa TSF3 has a remaining capacity of 3.4Mt. The LoM requires 28.2Mt TSF capacity, resulting in a shortfall of 24.7Mt. This will be mitigated through the elevating of penstocks to run TSF3 until decommissioning and TSF4 construction is complete. TSF4 will provide additional capacity of 55.0Mt, a surplus capacity of 31Mt.

Key developments and brownfield projects

The North Hill Feasibility Study has been completed and presented to the JV Board. North Hill is being considered as a life extension for Mimosa due to mining depletion risks at the South Hill from 2029 onwards. It is estimated that the current South Hill Mineral Reserves will sustain the operations until 2034. It targets an area with 6.65Moz 4E Mineral Resources, and will extend the Life of Mine at current rates (+230kOz per year) to ~2044 (+8 years).

Surface exploration drilling is being carried out in Mtshingwe and Wedza West sections to convert Indicated to Measured Mineral Resources and eventually to proved Mineral Reserves.