Tag Archives: Condra

Condra to show off crane building abilities on South Africa coal mine dragline contract

Bulk handling, Equipment maintenance, Mining consumables, Mining equipment, Mining maintenance, Mining safety, Mining services, , , , ,

Condra is to manufacture a “technically complex crane” to service a dragline at a coal mine in Mpumalanga, South Africa, following a contract win by its authorised agent for the Witbank region, GTB Industrial Services.

The order, won against strong competition, calls for a maintenance crane capable of working within the very constricted area of the dragline house. This contains motors and gearboxes controlling the excavating boom and dragline, and large hydraulic cylinders to control the pontoons, meaning space is at a premium.

Condra said: “Condra proved better able than its rivals to meet the complex criteria of the specification, chief of which was the requirement that the hoist be capable of separating completely from the maintenance crane, and moving away along individual roof beams as an independently operated underslung hoist to recover machine components to the central working space.”

The hoist must also be able to independently deliver loads to transport waiting outside the dragline house, should component repair within the house not be possible, the company added.

The requirement was met by designing the crane’s 12.5 t hoist as a beam changing machine, and fitting the crane with an interlock to prevent the hoist from leaving it unless the crane is securely connected to the selected beam, according to Condra. Power to the hoist is supplied via a cable drum instead of by the crane’s cable loop system.

Managing Director, Marc Kleiner, said Condra was able to draw upon previous experience of dragline maintenance cranes, overcoming engineering complexities to deliver a machine that allows a single hoist to carry out work that would more usually be undertaken by multiple units.

“Our design office tabled an innovative proposal that was also able to deliver more working room than our competitors,” he said. “We can quite often pull a rabbit out of the hat when nobody else can, but we think that this time it was also our ability to manufacture within a short lead time that helped win the order (lead time for the contract is just 14 weeks).”

A key component of Condra’s overall design for the crane is its manual beam interlock, which incorporates an anti-derailment limit switch to prevent hoist movement until beams are locked together, the company said.

Besides rendering impossible any movement of the hoist close to the end of the beam, this design also delivers the large tolerances needed to cope with beam movement when the dragline moves position, according to the company. Dragline movement takes place by ‘walking’ on pontoons repositioned for each step, tilting the machine house forward and placing stress on the structure as well as on the crane itself.

A hoist from Condra’s K-Series was chosen for the design because of its adaptability and particularly robust construction, well suited to these stresses, the company said.

K-Series hoists are produced in three main configurations: foot-mounted, underslung monorail and double-rail crab. Fully covered hoists in the series provide lifting capacities to 32 t, while open-drum units have capacities in excess of 250 t (open-drum and closed-drum Condra K-Series hoists are featured in the photo, painted green).

Features on all models include electromagnetic DC disc brakes, standard frame-size motors with parallel rotors, double-acting limit switches, solid bronze rope guides and totally enclosed splash-lubricated gearboxes. Lifting and reeving arrangements include centre lift.

Condra says it will deliver the dragline maintenance crane during the month following the easing of COVID-19 quarantine restrictions.

Condra delivers fully automated overhead crane to South Africa PGM operation

Automation, Mining equipment, Mining services, , , , ,

Condra says it has developed fully automated overhead crane capability, with the first machine of this type recently delivered to a South Africa platinum group metals operation.

Marc Kleiner, Condra’s Managing Director, said the company was making full use of new developments in sensors, controls and software to offer a very precise positioning capability in automated applications, with the company aware of an industry shift towards more automated operations.

“This is a capability that we will offer to our customers as an option,” Kleiner said. “We will mainly, but not solely, target the copper mines, especially tankhouse and copper-leaching applications where we have extensive experience.”

Condra’s announcement follows the increasing sophistication of its semi-automated installations, which began in 2003 with a grabbing crane installed at a Durban spice company to pick spices and transport them to specific points for release over hoppers, the company said.

At Sibanye Stillwater’s Marikana platinum mine (owned by Lonmin prior to Sibanye-Stillwater’s acquisition of the company), the fully-automated machine recently installed and commissioned is a 16 t, 16 m-span double-girder electric overhead travelling grabbing crane. It features a customer-specified mechanical rope grab in place of the hydraulic alternative to deliver the improved durability of mechanical operation within Marikana’s abrasive operating environment, Condra said.

There are dual hoists in the design; one to raise and lower the load, the other to mechanically close the grab by means of an internal sheave arrangement to overcome the spring-loaded open state.

Variable speed drives are fitted throughout the crane, delivering maximum speeds of 10 m/min on the lift, and 20 m/min and 40 m/min on the cross-travel and long-travel respectively. Four long-travel motors deliver the materials handling equivalent of four-wheel-drive, enabling automated control of all four wheels for precise crane positioning accurate to within 5 mm.

The crane is fully automated with a manual override, according to Condra, and is programmed by an operator from a remotely located control room, where on-screen monitoring is complemented by visual monitoring capability via closed-circuit television.

Condra’s fully automated option applies across the company’s product offering of single girder and double-girder overhead travelling cranes, gantry cranes, bridge cranes and cantilever cranes for markets worldwide, it said.

These machines go up to heavy duty Class 4, with a focus on product quality and reliability to the standards of ISO, GOST and other internationally recognised quality control bodies, Condra said.

Two lines of hoists are manufactured in several standard models suited to most mining, industrial and general applications, from 1 t to 500 t, with motors bought from external suppliers.