Winding engines go for gold

Qualter Hall, a UK-based mine shaft and hoisting specialist, has completed a £1.5m ($2m) contract to design, manufacture and supervise the installation of two new winding engines with associated shaft signalling and control systems.

The project was commissioned by Kahma Mining Corporation to extend shaft access to its Bulyanhulu gold mine in Tanzania, where mine depths below ground reach 1,260m. Both winders are capable of accessing depths to 1,585m.

Operation of the first winder is in men/material mode from a central control station, manned by an operator responding to signals from people on board. Driven by a 200kW motor, this single drum rope hoist is capable of transporting six people or 600kg of materials.

The 2.1m diameter drum of the first winder is manufactured in one piece and can accept three layers of rope. Braking is a disc system with failsafe operation and secondary backup features. Full testing facilities, guarding and manual controls are built into the assembly, while PLC controls and winder protection are the electrical system, together with regenerative braking to safeguard against mechanical brake failure.

The second winder is semi-automated with a safe load capacity exceeding 8t. It is used for transporting ore in two skips travelling in opposing directions at speeds of up to 16m/sec. The double skip assembly not only improves production efficiency, it also has a counter balancing effect which improves energy efficiency.

Incorporating a 3m diameter double drum rope hoist to accommodate both underlay and overlay ropes, the materials winder is powered by two 1,305kW motors operated through a helical gearbox. Drive to the fixed drum is via friction drive belts, while drive to the loose drum is via a multi-toothed clutch which engages with a clutch ring fixed to the drum side.