Mining equipment and fittings
In Várpalota, one of our sites in Hungary, the planning and manufacturing of hydraulic shields dates back to several decades. In the last decades, Várpalota Coal Mines and its successor companies have established a design and production capacity which manufactured shield types suited to a wide range of mining conditions in Hungary and in other countries with advanced mining industry. Our professionals engaged in the design and manufacturing of shields have earned a good domestic and international reputation for our company. Our company, as part of the Weldminker Group, continues to design and manufacture the Várpalota Hydraulic Shield (VHP) and its components, dating back to more than 50 years, under the direction of a chief engineer with several decades of experience. Based on the tens of years of experience in shield design and production, our company now engineers and manufactures the new and upgraded types of Várpalota Hydraulic Shields. Thanks to the high level expertise and technical experience of our shield engineers, besides the general, we are able to provide solutions for special conditions and cases. For example, the shield for roof coal caving is suggested to be used in case of varying coal seam thickness, while our specially designed shield types should be used in the crossings of drifts. We are open to engineering and manufacturing even for special cases and complicated floor and roof coal conditions.
A VHP-WMK- 101 SELF PROPELLED HYDRAULIC SHIELD
One of our products is WMK-VHP-101 self-propelled hydraulic shield which serves for supporting the caving of horizontal or low-angle dip (max. 20-25 °) coal seams with intermediate thickness. The equipment is suitable for mining a 2.5-3.1 m thick coal seam with a shearer cutting machine. If the coal seam is thicker or its thickness varies, the roof coal can also be extracted through a door operated by hydraulic cylinders, installed in the back of the shield. The equipment enables the application of tunnel shields at the crossings of haulage and ventilation drifts.
Scope of application
It serves for supporting the caving of horizontal or low-angle dip (max. 20-25 °) coal seams with intermediate thickness.
The structure and operation of the shield enables the application of a rack motion bucket wheel shearer cutting machine.
The length of the caving is determined by the designed caving system, the rock mechanics and the capacity of the conveying machinery used in caving.
The cradle system enables the configuration where the shoe stretches underneath the conveying machinery. This way the length of the shoe can be extended, which increases the shield surface on the floor, whereby decreasing the pressure exerted on the floor. This enables the application of the equipment even on floors with lower strength.
The equipment is suitable for mining a 2.5-3.1 m thick coal seam with a shearer cutting machine. If the coal seam is thicker or its thickness varies, the roof coal can also be extracted through a door operated by hydraulic cylinders, installed in the back of the shield.
If it is hard to cave in the roof coal, blasting can be used to trigger the process. If the roof coal contains waste bands and it appears at the door, it is always an option to close it, this way improving the quality of the coal.
The equipment enables the application of tunnel shields at the crossings of haulage and ventilation drifts.
EQUIPMENT STRUCTURE
The equipment is cradle shaped with lemniscate support system.
On the top, a catch device – operated by a hydraulic cylinder – blocks the coalface from tilting outwards. Its peculiarity is a door – operated by hydraulic cylinders – on the back of the shield, through which the roof coal can be fed to the face conveying machinery.
The device is made by welded high-strength steel sheets to decrease the dead load.
The mechanical structural units are rivet joined, welded box frame elements.
The strength and operation of the device is provided by a high-pressure (350-500 bar) hydraulic system.
Being equipped with such a device at the face, the safety of the personnel is ensured by the following:
VHP-WMK-101 ROOF COAL CAVING SHIELD
MAIN TECHNICAL SPECIFICATIONS
MAIN MINING SPECIFICATIONS