Imphisi Plant member Ian Macaulay explains that the excavator yarder has many benefits such as guyline-less anchoring and mobility. “The excavator yarder does not have to be anchored in the soil as the sheer mass of the excavator carrier is enough to keep the yarder stable. In cases where extra stability is needed, the boom and grapple can be used as an additional anchor. The guyline-less setup also saves a lot of time,” notes Macaulay.
He adds that the tracked excavator carrier enables the machine to manoeuvre over and around difficult and steep terrain. “Other cable-based harvesting applications that are anchored into the soil cannot be moved. This can create some logistical problems.” Another beneficial feature of the URUS III UNI 300 is its grapple head which can move logs around or wedge them back into position. In addition, the yarder is designed to be compatible with other excavator carriers and can be used in a skyline or shotgun carriage configuration.
The main components of the yarder excavator include the excavator carrier, boom, arm, grapple head, pulley, winch, carriage, chokers, mainline, haulback line, operator’s compartment and engine. A standard machine’s capacity is 300 m uphill or downhill, however, this capacity can be increased on request. The hydraulic system has been designed to be a bolt-on kit. The system T’s into the existing system, taking pressure and flow from the excavator’s existing pump, the machine automatically switches from normal excavator function to winch mode when controllers are activated.
Further, Macaulay explains that the 20 ton machine pulls about 1,8 tons to 2 tons of logs downhill, at a time. This is about five or six 18 m to 20 m logs, weighing in at around 350 kg each.
The Barberton operation requires only about six operators. One worker operates the machine; three others use chokers to hook the logs up to the carriage at the top of the hill where the trees are felled. Two more workers are involved in the de-choking process, which entails loosening the logs from the carriage’s grip.
A Hin-Tech three-wheeler with grapple is used to move the logs from the landing to the logyard and is used to stack the cross cut timber. Safety is a priority at the Imphisi Plant harvesting operation.
Macaulay adds that several additional safety procedures have been implemented at the operation. “Safety remains important in any harvesting operation and we have bolstered our safety procedures as we are logging in a very steep, slippery and remote area.”
Lastly, Hinteregger and Macaulay explain that they co-developed the excavator-based yarding system in 2000 and have since then made several design improvements before only recently perfecting the URUS III UNI 300.
Macaulay has eight URUS cable yarders and four Hin-Tech loggers in operation throughout South Africa and all of them have been manufactured in the country.