Monorail-mounted drilljig developed and patented

25th April 2003 By: Marius Roodt

A new drilljig is set to revolutionise mining in South Africa, says DDT Mechanised Mining Services director Dennis van Niekerk.

The new DDT drilljig sits on a cradle that is suspended from a monorail on the mine tunnel’s roof.

This practically eliminates the weight of the drill, making it easy to manoeuvre and adjust.

Conventional drilljigs are normally extremely heavy and difficult to move.

Further, women are becoming increasingly common as labourers on mines around the country, and often drilljigs are simply too heavy.

In addition, many young men are no longer interested in becoming machine operators and drillers.

Many mining recruits have matric qualifications, and want to do an intellectually challenging job, not one that simply needs brawn.

Many of them want to work on mines that have been mechanised.

Van Niekerk says the average age of a drilling machine operator in Rustenburg is 47.

It is thus clear that workers are also getting older, with young men not replacing those retiring or reaching middle age.

However, workers using the DDT drilljig do not even break out into a sweat, says Van Niekerk.

The accuracy of drilling is also not as easily influenced by operators as with a conventional drill, due to a stabilising arm that keeps it steady, resulting in increased drilling accuracy, and making the creation of a hole easier, he adds.

Because the jig is suspended from the roof it is never affected by conditions of the footwall.

The angle the machine operates at is also easily adjustable, and can turn 360 degrees without a problem.

On a normal drilljig one has to lift or hold the contraption to allow for a change of angle, says Van Niekerk.

This is often difficult and can cause accidents, as well as unsatisfactory, inaccurate drilling.

It also only takes about ten minutes to set up this drill, from hanging it on to the monorail, and setting up the cradle, to start of operations.

Van Niekerk explains that to set up a conventional drillrig takes between one-and-a-half and two hours.

The drillrig will also have a longer life than a conventional drill set-up.

This is because it can simply be pushed around, and is not manhandled like a conventional drill, which is carried from place to place.

Van Niekerk also believes the monorail for the rig can be used for other transport applications, such as timber, but not heavy goods.

The roofbolt’s presence, which the DDT jig’s monorail is hung from, also results in there being extra permanent support at the hangingwall, due to the monorail’s roofbolts.

The drilljig components are all standard, making it easily adjustable and affordable.

Other advantages of the rig are that less waste is created when drilling, due to its accuracy, hangingwall damage is lessened, and it is also user-friendly.

The DDT drill has an automatic brake, so that if it slips out of an operator’s hand, it will stop automatically, which is especially useful on a steep dip.

The rig is currently being tested at Impala Platinum.

Testing began in November last year, with the design being patented in July last year.

Impala Platinum has the sole development rights until February next year.

Van Niekerk confides that a decision will soon be made on whether the platinum-miner will acquire the new drilljig, but he believes the result is already a foregone conclusion.

He says management at Impala Platinum were extremely impressed with the machine, and have confidence in its success.

Van Niekerk tells Mining Weekly that, on a standard 30-m-long panel, with a one-metre stoping width, the cost of the machine will be about R70 000.