Eagles undisturbed by noise at Oetelshofen quarry

Minimising environmental impact is a key concern of the management and staff of the Oetelshofen quarry company in Wuppertal, Germany.  Formed in 1900, the company now employs 95 staff, produces 2 million tons of limestone products, and annually turns over 35 million Euros. But although they have experienced impressive growth over the last few years, they are keen to ensure that operations continue in an environmentally friendly manner as is possible.

To maximise its productivity but minimise environmental impact, Oetelshofen has invested in brand new firing technology, as well as recently switching to the latest in Sandvik wear protection. Moritz Iseke, joint managing director, explains: "Our recent investments in equipment at the plant means that for the next 50 years the quarrying of high quality limestone at this site is safeguarded. When we have exhausted those resources the engineers will have to deal with quarrying below groundwater levels."

Operational efficiency is not the only concern for the company as being proud Wuppertal natives the integrity and sustainability of the operation is of primary concern.  In Moritz Iseke own words: "Besides caring for our employees, we also feel committed to the natural environment, and consider it our duty to protect our neighbours from any emissions from the plant. This of course includes the reduction of any noise emissions."

The company initially looked to Sandvik for assistance when lining the 6 m² feed hopper of a kiln. This was accomplished with Sandvik's WT7000 dual hardness rubber wear plates. The modular system was easy to install, and reduced the noise emissions by 50% as experienced by the human ear. Six months later the company management decided to equip the new 120 m² hopper, again with  WT7000 rubber linings.  The dual hardness structure of the linings made a great impression with the company management who were keen to enjoy the same benefits they had experienced with the kiln hopper.

A major challenge however was to choose the right material for the hopper, which has been designed to deal with an annual production capacity of 500,000 tons of limestone. The hopper requires a heavy duty lining as it will be loaded by a 60 ton capacity truck, with a product size of up to 140 mm. 

After discussions between management and Sandvik technical staff, it was decided to use 1,500 pieces of 50 mm thick rubber liners mounted with welding studs. This has proved to be a particularly attractive solution as when the sharp edged stone has worn out the plates the individual 300x300 mm modules may be quickly, cost-effectively and safely replaced. 

As the liners are made of dual hardness rubber, without any steel reinforcement, they are easily cut out and fully recyclable. Sandvik's project manager for the site installation, Selim Sahin, explains: "Thanks to this patented modular system the base of the hopper is protected against cracks and deformation. It therefore retains its original shape, and the liner lip protects against fines infiltration between the gaps. In addition to those benefits, the service life is tripled. None of these features are achievable with conventional steel linings."

Outlining some additional benefits to the neighbours of the quarry, Moritz Iseke proudly states: "The quarry hosts the largest European Eagle Owl population in Europe. On average three owls per year are hatched at the Osterholz limestone quarry, and as the quarry operate only two shifts, these flying night hunters will be grateful to Sandvik for their peaceful rest during the day."

Due to the success of the installation, the protection of the eagle owls and improvements in operational performance, Oetelshofen is now considering using Sandvik wear protection at the limestone quarry for all its future plans.  Discussions are already ongoing at the site involving product and material testing, with new applications such as lining truck boxes or using ceramic / rubber wear protection liners - but not at the expense of the locals - human or eagle owl.

www.miningandconstruction.sandvik.com