Mining in Swedish Dannemora came to a halt in 1992 because the price of iron ore could no longer sustain the operation. Now the market is booming, and Dannemora Mineral AB is trying to get the mine dry and back in business.
DANNEMORA LOOKS very much like any other small town in Sweden where mining once dominated and then ceased to exist. Next to an open pit, mined for centuries, a shaft tower of later vintage looms over a mix of historical buildings and old mining infrastructure. The underground mine closed in 1992 because the market price of iron ore was too low. Today, driving through town, it feels more like an outdoor museum than an active mining village.
But get out of the car and you will see that things are indeed happening in Dannemora. In the ore stockyard, dumper trucks are shedding their load for further treatment to lump ore. Some of it will soon be shipped as the last of six test deliveries to steel mills in Europe for evaluation. This revival is a result of a market boom in iron ore, and the entrepreneurial eff orts of Dannemora Mineral AB to get the mine back in business again. With the required official permits already in hand, the response to the test deliveries will be crucial.
“With signed delivery contracts, we can approach the bank to get continued financing,” says Kjell Klippmark, managing director of Dannemora Magnetit, the subsidiary in charge of the actual mining. “All the homework has been done,” he says. “Now it’s only the customers that remain.” While the test deliveries have been carried out with provisional equipment, continued operation requires more permanent solutions. Klippmark worked for almost three decades in different jobs within mining giant LKAB’s operation in the north of Sweden, and is familiar with the technical challenges. The trick, he says, is to prioritize and coordinate the activities involved in reopening the mine.
“The actual construction work includes five subprojects,” says Klippmark. These comprise a processing plant, an underground access ramp, an elevator frame, mine ventilation and, not least, infrastructure. The latter includes upgrading a railway and a shipping port in the Baltic, as well as building a power supply and a drainage system in the mine. Drainage, however, required an unusual first step: getting rid of the water in the main shaft and drifts that had accumulated at a rate of 10 meters a year (30 feet) since the mine was closed in 1992.
The bottom of the main shaft is 620 meters (2,035 feet) below ground. Th e water had reached 323 meters (1,060 feet) when the tender was issued in 2007. Twenty-three meters (75 feet) up, at the 300-meter (985-feet) level, was a drift where a temporary pump assembly could be squeezed in, which would simplify the whole operation. But as the planning went on, water kept rising. In 2008, a consortium consisting of Xylem and underground specialist Bergteamet was assigned to the task.
“It was a challenge to stick with the time schedule, as we were setting up at the 300-meter level and the water kept rising,” says Björn Lindström of Bergteamet. He is project manager for the underground installation of the pump assembly, designed and delivered by Xylem.
Judging from his calm appearance, Lindström doesn’t look like somebody who normally gets worked up about things. But with a drift full of mud, no electric power and water gushing down the walls of the shaft, there were a few things that had to be dealt with in order to get the equipment into place. Until a hoist was installed, visits to the 300-meter level had to be made on ladders.
In May 2009, with a water level of 311 meters (1,020 feet), the pumps were in place and went into action. By February 2010, the level had reached the contractual 465 meters (1,525 feet) required for the fi rst phase in the revival of the Dannemora mine, relieving it of 3 million cubic meters of water. If everything goes as planned, including the test deliveries of iron ore, the mine will be completely drained and in operation with a permanent dewatering system from Xylem by 2012.