Modern Mining May 2023

DIAMONDS

Mine ventilation and refrigeration specialist BBE Projects was recently contracted to design, supply, construct and commission a turn-key air-cooling system for the Venetia Diamond Mine, which is approaching the final stages of its transition from open pit to underground mining. BBE completes refrigeration and air-cooling system for VUP

Andrew Branch, Director at BBE Projects.

D e Beers’ Venetia Diamond Mine has been South Africa’s biggest producer of diamonds since 1995. Today, the mine produces 5.5 mil lion tons per annum and will ramp up to 5.9 million tons per annum with the underground contribution. About a decade ago, De Beers embarked on the Venetia Underground Project, a $2 billion proj ect designed to transition the mine from open pit to underground. The underground infrastructure comprises two vertical shaft systems for personnel transport, ore transport, routing of services, lateral access levels on 54, 94, 100 and 103 level, and shaft bottoms at 107 level. In addition, the need for cooling was identified as part of the ventilation and occupa tional hygiene planning for the underground mine. BBE Consulting, a company of the BBE Group, has been involved in the Venetia Underground Project since the Pre-Feasibility phase, engaging from an early stage to help with the planning for the transition to underground mining. As a result, BBE was in the

position where it could deliver the air-cooling system relatively quickly – from submitting a bid to contract ing for the project. The first contract was signed in April 2018. BBE Group is unique in the market in that mine ventilation and cooling is its sole business. However, a major challenge proved to be the out break of the Covid-19 pandemic, with lockdowns and additional health and safety protocols affecting pro ductivity on site and manufacturing off site, as well as the availability of parts and equipment. Despite this, work continued, and the air-cooling system is now in the final stages of being commissioned. The air-cooling system constructed by BBE Projects includes two water-chilling refrigeration machines housed in a central plant that distributes chilled water to several users, as part of a distributed cooling approach. The main air cooler, a direct-con tact spray chamber located adjacent to the plant building, will eventually feed cold air to the under ground workings via a large downcast shaft, which is currently being raise-bored by a specialist contrac

De Beers’ Venetia Diamond Mine.

tor. BBE Projects will return to the project within the next eight to ten months to install the final piece of duct connection between the spray chamber and the downcast shaft once the raise boring is complete. There are three subsidiary air coolers operating – a secondary spray chamber feeding a satellite downcast shaft, which supplies cold air to the development work ings; and two finned-coil dry heat exchangers in the air intakes to the sinking fans which force-ventilate the production shaft. These cool the air as it enters the shaft for workers performing shaft sinking, equipping and underground devel opment work. “One of the main reasons BBE was chosen to participate in the Venetia Underground Project is its proud history of success in South Africa and internationally,” says Andrew Branch, Director at BBE Projects. 

16  MODERN MINING  May 2023