High above the plateau at Jamaica’s Mount Oliphant is a technology that would traditionally be more at home in a ski resort than at a bauxite mine in the Caribbean.
An almost silent 3.4km-long Rope Conveyor (RopeCon) system whirls overhead, transporting bauxite from Alcoa’s South Manchester mine operation to St Jago, Clarendon, where it is moved by train to the US producer’s refinery around 20 miles away at Halse Hall.
Looking at first glance uncannily like a lift to transport skiers across the mountains, RopeCon was completed within 16 months in 2008 using transport technology by Doppelmayr, an Austrian company that makes chairlifts, cable cars, gondolas and surface tows for skiing. The system belt has corrugated side walls and integrated wheel sets running on fixed track ropes, guided over eleven tower structures.
It takes bauxite from the South Manchester plateau at Mount Oliphant, down to the rail head at St Jago, Clarendon. Alcoa processes bauxite at the Clarendon refinery, a majority-owned joint venture called Jamalco, with the government owning the remaining 45% stake.
By modern road standards, the distance is relatively short. But to transport the 14,000 tpd that is moved would have needed 1,200 truck journeys, back and forth along the narrow and winding roads of Jamaica.
“The conveyor unlocks inaccessible terrain; we couldn’t use trucks,” Leo Lambert, corporate services and government affairs manager, said.
“One of things about the RopeCon system is the noise control mechanism. If you listen, the decibel level is minimal. Now that has to be compared to a truck, if we were to use trucks to do the transportation,” he added.
It takes just 18 minutes to get bauxite, carefully sampled and sifted, along the length of the system and to St Jago. The system transports around 1,000 tonnes an hour. An average 3.2 million tpy of bauxite is moved in this way.
The mid-air rope conveyor has other benefits: it’s environmentally friendly, eliminating around 160,000 tpy of carbon dioxide emissions, Alcoa estimates, while disruption to the local landscape and communities is minimal. The system is extremely quiet, and there is no dust nuisance.
The system also creates green energy: as loaded bauxite begins its descent, the conveyor starts operating in continuous braking mode, generating energy proportional to the weight of the load. The 1,200 kW per hour on average that RopeCon produces is enough energy for six Jamaican households.
Some of this green energy is used to power the mine facility and the rest is sold to the national light and power company.
The similarity to a ski lift is not entirely inaccurate. RopeCon actually uses a small ski lift on the conveyor itself to carry out maintenance of the elevated system.
Mine superintendent Glenroy Lawrence told Metal Bulletin that the company has three years after it removes bauxite in which to reclaim and rehabilitate the mined land.
“In simple terms, this means we reshape the landscape so it can be put to other viable use. The most popular use is for agro, meaning that we plant it back with fruit trees or crops, or we use it for cattle rearing. The latest thing we have done is that we reclaim and rehabilitate to an extent that the land can be used for resettlement housing,” he said.
Other projects include greenhouses and schools, Lawrence added.