Engineering services company Master Drilling will next month complete a diamond mine pilot project aimed at roughly doubling the drilling rate and cutting costs, as miners turn to technology to maximise output from depleted reserves.

Although they have recovered from a deep downturn in 2015, miners face the challenge of rising exploration expenditure after the easiest resources have been extracted.

Many companies are experimenting with new ways of cutting into mineral deposits to improve profit margins.

Master Drilling, working with diamond producer Petra Diamonds at the Cullinan mine, northeast of Johannesburg, is near the end of a three-year trial that accelerates drilling by using a giant drill-cum-vacuum cleaner to power horizontally through diamond-bearing kimberlite.

It says the test-phase should end in March, offers the prospect of increasing drilling speeds from around 3 metres to up to 6 metres per day and has applications beyond mining.

“We see this trial as an opportunity to establish a reference for ourselves in getting involved in tunnelling and building knowledge and expertise,” Koos Jordaan, a director at Master Drilling, told Reuters at Cullinan, famous for producing diamonds used in Britain’s crown jewels.

The result of using a drill rather than blasting is a perfectly round tunnel, which engineers say is a more stable shape than the irregular tunnels created by blasting stone.

Safety is further improved because miners have less exposure to the pit face and, as more ground is covered more precisely, the chances of striking gem-rich ore increases.

While Master Drilling says the technology can be applied to other types of mining such as copper, using a vacuum – eliminating the need for water to douse down the dust – is particularly relevant to kimberlite, which dissolves in water.

The company declined to comment in detail on the cost impact until full analysis of the pilot is completed.  

Other miners are also using new methods and seeking to replace traditional blasting.

Anglo American Chief Executive Officer Mark Cutifani said at the Indaba mining conference in Cape Town, South Africa, on Monday that the modern mine would be one “where continuous rock-cutting machines safely extract the targeted ore – deep underground – without the need for explosive blasting”.

The company says the shift has safety benefits, cuts the amount of time needed for extraction and improves the ability to accurately target mineral-bearing ore, rather than waste rock.