The Zimbabwe Independent

Bitumen World’s Lutumba Quarry

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LUTUMBA Quarry grunted into life on July 15, 2021, in a cloud of dust, initially spitting out crusher run for our next phase of the constructi­on project towards the completion of rehabilita­tion between Beitbridge and Harare.

Currently, there are two sets of crushers with their associated personnel and support equipment. e plan being that every month one would produce 20 000 tonnes of crusher run and the other 6 000 tonnes of surfacing and concrete aggregate.

Each product must satisfy certain quality and grading specificat­ions to meet the stringent Ministry of Transport requiremen­ts.

All aggregates are normally produced using two different types of crushers. e first being a jaw crusher which crunches the rock between a set of jaws moving just like the jaws of a crocodile.

e second crusher is called a cone crusher. is crusher moves in a circular grinding motion between the concave and the mantle. Imagine a pestle and mortar being used in a grinding motion for making peanut butter and you get the idea of how a cone crusher works.

If the grading of the material being produced does not fit between the lines of a grading envelope, it’s possible that a third type of crusher could be added to ensure suitable quality crushed product. is third type of crusher is called a Vertical Shaft Impact (VSI) crusher. e VSI produces aggregates that are mostly cubical in shape as opposed to being what is termed “flaky” (elongated aggregate).

e VSI Crusher works by feed material dropping through the feed tube onto the impeller table or enclosed rotor which, through centrifuga­l force, throws the material against stationary anvils made up of composite metal alloys.

e crushers are supported by a number of excavators and tippers which are used to haul the blasted rock from the quarry to the crushers.

Another set of excavators, feeds the crusher’s themselves, with a pair of front-end loaders moving the material into stockpile.

Between August 2021 and March 2023, it is envisaged that the quarry will produce approximat­ely 400 000 tonnes of crusher run and surfacing aggregate for the Company.

Lutumba, unlike Tsomboli, which is an exposed surface rock, is a rock just apparent on the surface, meaning that once the quarry is closed down after extraction of the estimated 400 000 tonnes of aggregate, there will remain quite a large hole in the ground which will need careful rehabilita­tion to ensure that it does not become an eyesore or a hazard to humans and animals alike.

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