Tyre protection in the limelight
Headquartered in Goslar, Fels-Werke GmbH is one of Germany’s leading quarrying companies and ranks second in the supply of limestone products. In Germany, Fels owns several quarries, operates eight lime production plants and one dolomitic lime plant. In the Czech Republic, Fels has a quarry and a lime production plant and, with the 2009 commissioning of a lime production plant south of Moscow, Fels has established a foothold in the Russian Federation. The company sources its raw materials from wholly-owned Devonian, dolomitic and Jurassic limestone deposits identified for their purity and homogeneity.
Fels claims a combined crushing capacity of just under 3 Mt and, with a total of 46 kilns, an output of more than 0.3 Mt/a of hydrated lime and over 2 Mt/a of high-quality quicklime. In all, Fels employs some 1000 people, produces over 5 million tonnes of limestone products and generates revenues of around 250 million €/a.
Fels’ skilled technicians exercising rigorous quality control and advanced crushing, pulverising and calcining processes create a comprehensive range of primary products including; aggregates, un-burnt coarse, medium, fine and pulverised limestone; lump, fine ground and hydrated, high-calcium lime, quick-limes, milk of lime and lime putty and special limes in the form of fine ground lime and hydrated lime mixtures.
In agriculture, soil fertility and crop growth is improved with lime dusting while, in forestry, lime dressing counters the effects of acid rain. In sugar manufacture Fels’ “sugarstone” is essential for separating the liquor from beet pulp and cane trash.
Building materials such as bricks and blocks, mortar, cement and concrete are all derived from limestone. Our infrastructure – road, rail, earthworks, soil stabilisation – rests on limestone aggregates, asphalts and bitumen.
As key ingredients, Fels’ lime products are required to introduce various levels of calcium and alkalinity into chemical and metallurgical processes, as ingredients in ceramics, the manufacture of clear glass, wood-pulp, metallurgy and, in the form of lump lime, as a purifying flux in steel making.
As part of plans to quarry 6 Mt/a limestone, Fels is has add two Caterpillar Cat 990 and a Cat 992 to its load and haul fleet. One of the Cat 990 is destined for work in Saal at the Danube where Fels has access to a major deposit of high-purity Jura limestone. Operating nine kilns employing efficient processing and calcining technologies, Saal produces a comprehensive range of lime products in grades that meet a broad spectrum of industrial applications.
The second Cat 990 will be working at Kalkwerk Kaltes Tal (Fig. 1), a two quarry operation situated close to Brocken Mountain on the edge of the Harz National Park where some 1.5 Mt of pure Devonian limestone is processed annually by seven kilns including three annular shaft kilns and two counter-flow/parallel flow regenerative (PFR) kilns produce about 500 000 t/a of highly-reactive quicklime.
The Cat 992 will work in Fels’ Rübeland/ Hornberg complex. Also located on the fringe of the Harz National Park and quarrying the same Devonian deposit, this operation combines 10 state-of-the-art PFR kilns enabling to produce 600000 t/a of multiple grades of high-quality lime products for use in a large number of processes.
Teamed with a train of Cat 772, 50 tonne-haulers, powered by a 627 hp, Cat® C27 ACERTTM engine and equipped with a standard 8.4-9.2 m3 bucket, a Cat 990 can hoist a full truck load in four 15 tonnes-loads or, in high lift configuration, replenish a 90 tonne-truck in six passes. Caterpillar first introduced the 992 in 1968. The K series is ideally matched with Cat’s 777 series G dump trucks or their equivalent. Powered by an 814 hp, Cat® C32 ACERTTM engine and available with a 10.7–12.3 m3 bucket the 992 can deliver a 100 ton payload in just four cycles.
Laid down some 350 million years ago, Devonian is an extremely abrasive material that can rapidly destroy the tread of bare tyres and, at the working face, there is an ever-present risk of sidewall damage and blow-outs as the loader crowds into the newly-blasted rock fragments. Large earthmover tyres are in short supply and costly to buy so it is practical for Fels to take measures to obtain maximum value from their investment by ensuring their tyres last as long as possible.
For optimum efficiency and economy, the front tyres of the three Cats – the 990s take 41-25-70 tyres and the 992s are shod with 45-65-45 tyres – will be fitted with Erlau R71 Spezial tyre protection chains (TPC). It is a closed mesh, case-hardened, ring-ring chain that absorbs abrasion and protects against sidewall damage. The less vulnerable rear tyres will be protected from abrasion by pairs of the lighter Erlau R71 TPCs (Fig. 2).
In fact, the protection against the most extreme mining conditions is so effective that loaders of all sizes fitted with Erlau TPCs run safely on flaming hot steel slag without danger to operators or assets. So it’s no wonder that Erlau’s TPCs are found in leading mines and quarries across the globe – producing limestone in Europe, copper in Chile, iron ore in Australia and diamonds in Africa where they prove their worth on wheel loaders, dozers, motor-graders and dump trucks.
