GERMAN TECHNOLOGY
hard rock formations. It allows diameters of up to 1.5 m with a maximum boring length of 70 m and an inclination of up to ± 30 ° from vertical.
Herrenknecht has also started making new Shaft Boring Roadheaders( SBR), which are required for building the Nezhinsky potash mining and processing factory in Belarus, Belarus news agency BelTA learned from Anna Bunkova, press secretary of IOOO Slavkaliy, the company in charge of building the factory. Herrenknecht is contributing to the project to build the Nezhinsky potash mining and processing factory as part of the contract signed with Slavkaliy’ s contractor Deilmann-Haniel. Using the Shaft Boring Roadheaders( SBR) to make shafts will be a first for Europe.
Such machines have been used only once in Canada at the Jansen potash mine. Core components of the SBR machines are being manufactured now. Certain parts are ready for assembly. Herrenknecht will start assembling integral parts in March 2018.
Caterpillar longwall mining innovations
Caterpillar’ s longwall system design and engineering team is based in Lünen, Germany. The predecessor companies of what is now Caterpillar Underground Mining were key contributors to the development of longwall mining equipment, and much of that work has taken place at the Lünen facilities, which were once home to the Westphalia organisation. Westfalia Becorit formed in 1991, and in late 1994, DBT formed by integrating Westfalia Becorit, Hemscheidt and Halbach & Braun. DBT acquired Long Airdox in 2001, and Bucyrus acquired DBT in 2007. In 2011, Caterpillar acquired Bucyrus. Those companies created much of the equipment that has evolved into modern longwall mining.
Today, Caterpillar offers the latest longwall mining components – shields, armoured face conveyors, shearers, ploughs, stage loaders – and controls that integrate the components as one. The evolution of longwall technology now enables automation, which drives enhanced safety and increased production and mechanical availability.
For example, shearer automation enables running a shearer with only one operator instead of two, which means that no operator has to leave the fresh air end of the shearer. Additionally, the operator can leave the machine to itself in wide areas of the face. People spend less time in hazardous areas and are less exposed to dust and noise.
To suit customer needs, Caterpillar offers different levels of shearer automation, from basic to advanced. Each Cat ® shearer is equipped with a basic automation package, which allows the machine to be operated by remote control. This package also includes automation logic that can reduce overload situations, and of course it offers diagnostic tools for troubleshooting and problem-solving.
Caterpillar also offers two more complex automation packages: Automation Control and Advanced Automation Control. Automation Control includes important features such as extended gate end communication, which provides data exchange with other longwall components. This automation level allows the ranging arms to be operated in a high quality closed-loop operation for precise steering. It also provides a collision avoidance function to prevent collision between the shearer and the shields operated by Cat PMC-R controls.
The most important feature is State-Based Automation( SBA). SBA allows definition of the full cutting cycle of the machine along the face for both cutting directions between main gate and tail gate, as well as the cleanup operation at the gate ends. SBA allows the shearer to operate precisely according to the operator’ s defined production process— including directions, speeds, arm heights, cowl positions and ranging arm control modes. Users can define up to 500 states with actions and conditions to be met before the next state is entered. The system is also capable of defining up to 40 zones along the face for each of the zone-based parameters. This allows mine personnel to determine all imaginable variations in longwall operation cycles.
To simplify and optimise operation, Caterpillar has created several preset cutting modes that can be chosen in each automation state. Advanced Automation Control brings the system closer to fully autonomous shearer operation. This package includes a feature called Longwall Navigator, which combines Cat software tools in the gate ends and in the shield controllers into one package that offers advanced geometry and trigonometry calculations for full 3D navigation, as well as an advanced floor profile calculation and a high level of sensor technology.
These technologies make it possible to achieve horizon control, extraction control and face alignment. Extraction control allows the machine to follow defined floor and roof profiles along the face, better following any given coal seam undulations for optimal extraction and production. At the same time, horizon
The new Cat HTD4100 High Torque Drive System control guides the machine to follow the seam undulations in the direction of advance. Face alignment keeps the face straight for consistent production and minimal wear of the conveyor system.“ Longwall system automation is moving toward full gate end automation, teleremote operation and, ultimately, fully autonomous operation,” says Caterpillar.
Caterpillar engineers are also developing improved longwall components. Using variable frequency drive( VFD) technology and an innovative low-speed, high torque motor, the Caterpillar longwall team in Lünen is working to step up longwall face conveyor performance. The permanent magnet synchronous motor combined with the VFD promises multiple benefits, such as higher productivity and reduced total cost of ownership through low maintenance and high mechanical availability.
The new Cat High Torque Drive System is built around the low-speed motor, which delivers the same high torque at all speeds. The convertercontrolled torque motor operates at speeds between 0 and 300 rpm versus 1,500 rpm for induction motors. Lower speed reduces inertia acting on the output shaft by a factor of eight and enables the system to react quickly, which translates to little or no damage to the gearbox and conveyor chain in the event of a conveyor blockage.
JOEST’ s new double shaft screen
JOEST has developed a double-shaft screen for challenging screening applications. The screen allows a changeover from a linear motion to an elliptical motion in order to optimise the screening process for the actual consistency of the product. In the actual project in question, around 270 t / h of wet gravel and sand with a grain size of 0-120 mm were screened. This material is highly abrasive, sharp-edged and thus prone to clogging. Due to the twin-deck design, it is possible to produce gravel sizes of 0- 4 mm, 4-22 mm and > 22 mm. The special feature of this screen is that it can be operated both as a linear motion as well as an elliptical motion screen. This is made possible by a JOEST electronic control system in combination with the proven, overhead JOEST double-shaft drive. In addition, the new system with electronic control can variably adjust the angle of attack and the formation of the ellipse. The screen can therefore be precisely adjusted to suit the customer’ s screening requirements.
Conveyed material with a tendency to clogging is screened primarily with an elliptical vibrator. To ensure clear screen cuts, it makes sense to switch to a linear
18 International Mining | MARCH 2018