Aktualisiert: 8. Juni 2022
The mobile mining machinery of a quarry of the Mineral Group in Czech Republic is partly outdated and shall be replaced by new machines. In particular, the transport from the quarry to the crushing plant needs to be sufficiently dimensioned to meet the crusher´s maximum feed capacity of 220 tonnes per hour. An investment decision needs to be done based on a long-term analysis of the mining processes.
Mineral Abbau Gmbh – The Mineral Group is part of the STRABAG-Group and one on the leading raw material brands in Central, South-Eastern and Eastern Europe. With around 200 quarries and gravel pits, the Mineral Group guarantees an optimal supply of high-quality, mineral raw material for construction services and many other products in daily live.
For the recording of mining activities, the mobile machinery are equipped with devices from the abaut marketplace that were sent by postal service and easily installed by employees of the company themselves (approx. 10 min. per device).
In order to obtain a sound and objective decision basis for the selection and dimensioning of the new equipment, the basic mining processes are captured and analysed. Loading, unloading as well as the entire transport cycle from the extraction area towards the processing plant area are recorded in detail over a long period of time. Especially not desired time shares such as queuing at the crusher or time losses throughout the whole day need to be detected and reported for their occurrence in the mining area.
Loading and unloading times are analysed and reported in a very detailed way, showing the wide bandwidth of both activities.
By analysing the hourly transporting capacities it is shown that up to 377 tons per hour could be achieved as a singularity but much likely is a capacity of 170 to 229 tons per hour, especially with greater regularity of all other capacity classes.
This may be due to the fact that the capacity of the crusher is stated to be 220 tonnes per hour. Larger transporting capacities are prevented by the "bottle neck" crusher. Therefore, large transporing capacities are only singular hourly capacities, which are compensated by weaker capacities before and after these hours.
As a result it could be found that instead of the two existing dump trucks, having a payload of 45 and 28 tons, 2 dump trucks with a payload of 36 tons each will be used. If cycle times similar to those of the trucks to be replaced of around 15 minutes are taken as a basis, a maximum of 288 tonnes per hour can be transported, without taking into account the possible higher speed of the new trucks.
If one also improves the feed hopper to the crusher and the crusher capacity itself (elimination of the "bottle neck", a regular transport capacity of around 300 tonnes per hour is realistic.
A similar effect can be achieved by setting up an intermediate storage facility. This equalises both transport and processing mass flows. This leads to more constant cycles from the quarry to the processing plant and at the same time to a constant utilisation of the plant.
The two new trucks are to be loaded with a hydraulic excavator in the 40 to 45 tonne class.
The technical experts from Mineral Group did not need to visit the quarry to take the right investment decision, saving time and valuable resources.