Schleswig-Holstein-based Ohle & Lau GmbH gravel quarry has been an allmineral customer since its inception, producing top quality gravel for more than a quarter of a century.

For more than 25 years, an air-pulsed alljig® wet jigging unit, working in gravel, has reliably and efficiently played its part in the beneficiation of the quarry’s raw material into gravel of the highest quality and purity.

One of the notable benefits of the air-pulsed alljig is that it can be finely tuned to guarantee the separation of alkali-reactive components in the gravel, which – inter alia – can cause significant damage to concrete constructions such as bridges, pavements and many more.

Gravel and sand are valuable raw materials for many industrial sectors – especially the building industry, which depends on an adequate and consistent supply. The allmineral alljig provide a distinct advantage in the Schleswig-Holstein region where the gravels show relatively high proportions of alkali-reactive components, thus limiting their usability in the production of concrete.

Meanwhile in the expansion and realignment of Ohle & Lau GmbH an alljig®G-1400, is in the process of being installed by allmineral and is expected to be operational in the next few months.

How the alljig works

The alljig® fluidizes the material to be beneficiated by pulsating water, which forms layers of grains according to their density. In so doing, a homogenous layering of the grains according to their density takes place and the alljig air-pulsed wet jigcan be accurately adjusted to the small density differences between the gravel and the components enabling it to seprate the cleaned heavy material from the stratified material bed via the automatic discharge control.

Frequency, amplitude and timing of the water pulsation can be adapted during the operation, thus allowing the most precise sorting of the feed material. After the layering procedure the cleaned gravel is automatically discharged, screened, dewatered and finally conveyed to the raw materials warehouse via belt conveying systems.

The efficient separation, concentration and cleaning of the raw gravels, which, in dry quarrying, are conveyed to the plant via wheel loaders, enables the two gravel quarries of Ohle & Lau to offer the building industry a uniquely wide range of high-quality products.

The new alljig® 1400 will further enhance Ohle & Lau’s well-established reputation for producing both the highest quality gravel, as well as being top-class, reliable partners for the building and other industries.