Paterson?s Quarries Ltd has been operating Dunduff Quarry in Kirkmuirhill since the beginning of the 1980s. The hard rock found in the quarry is dolerite originating from the Devonian period with inclusions of sandstone that has hardened under the influence of pressure and heat. The feldspar is of a reddish colour and is used as a decorative and high quality product on roads, carparks, driveways and in gardens. In addition, aggregate for concrete blocks as well as coarse-grained material for concrete and frost protection are also mined in Dunduff Quarry.
When the time had come to replace the outdated stationary plant, the choice was soon made for a mobile plant from Kleemann. A mobile solution was preferred, since it would allow more flexibility in terms of location and also involved reasonable investment costs.
?We chose Kleemann products for several reasons. For one, our experience with Kleemann plants in the past has been very positive. We also know that Kleemann simply has a profound process knowledge gained in several decades of experience in stationary plant construction, which they have often successfully transferred to mobile projects. Therefore, we were sure that we?d achieve precisely those results we were looking for,? explains Phil Doherty, the mine manager at Paterson?s Quarries Ltd in charge of Dunduff Quarry.
?The requirements did pose a great challenge, of course. A team of specialists is needed when switching from a stationary plant to a mobile system,? says David Norris, general manager of the Mineral Technologies Division at Wirtgen Limited. Today, the mobile plant combination from Kleemann successfully produces the six specified high quality end products: 0-3mm, 3-6mm, 6-10mm, 10-14mm, 14-20mm and 20-31.5mm. The new process design even requires no more than two cone crushers, unlike the old stationary plant which had required three, while producing an end product of higher quality at the same time.
In addition to high performance plants, many years of experience in applications technology are needed to be able to implement such processes successfully. Based on previously built mobile plant combinations and know-how from stationary plant construction, the engineers at Kleemann devised a coherent concept and made sure that it was implemented with maximum efficiency. In the final analysis, the excellent performance of the overall system and high quality of the end products can be attributed to the successful collaboration between Paterson?s Quarries Ltd, Wirtgen Limited and the Kleemann main plant.
PROCESS CHAIN TAILORED TO PRECISION
The feed material, which ranges from 0 to 600mm in size, is pre-crushed to 0 to 260mm by a Mobicat MC 120 Z mobile jaw crusher directly at the quarry face. It is particularly important at this stage to effectively screen the fines contained in the feed material as, in the next crushing stage, the material is fed to a mobile cone crusher type Mobicone MCO 11 by means of wheel loaders.
The MCO 11 crushes around 220 tonnes per hour of material to approximately 0 to 75mm in size, and then transfers it immediately to the second cone crusher, a Mobicone MCO 11 S, where the material is reduced to grain sizes ranging from 0 to 31.75mm. Upstream of the crushing unit, the MCO 11 S is equipped with a triple-deck screen that immediately transfers the 0 to 31.5mm grain sizes to the next plant, a Mobiscreen MS 17 Z double-deck screening machine.
In addition, the Mobicone?s 2000mm x 6000mm screen decks ensure that the crushing chamber in the cone crusher is filled steadily and effectively. The MS 17 Z screens two end products of 20mm to 31.5mm and 14mm to 20mm in size, passing the remaining material smaller than 14mm to the Mobiscreen MS 20 D mobile triple-deck screening machine. This extremely powerful plant separates and stockpiles a total quantity of more than 150 tonnes per hour of material into high quality final aggregate fractions of grain sizes 10mm to 14mm, 6mm to 10mm, 3mm to 6mm and 0 to 3mm.
Source: Wirtgen Australia Pty Ltd