Benefits of the software include reducing damage on the mechanical and structural elements of the shearer, reducing breakdown maintenance and catastrophic failure on the longwall face, and minimizing respirable dust and fines.
The software is now being further developed by CRC Mining at the University of Queensland in Brisbane where key researcher, Dr Bulent Tiryaki, has secured a three-year research fellowship.
Dr Tiryaki conducted the initial work at the Cayirhan longwall mine, Turkey’s first fully mechanised longwall mine located near Ankara, established in the mid-1980s. The development of the software was aimed at analysing machine vibrations during coal excavation with shearers, known to be a major cause of mechanical, electrical, or hydraulic failure. The underground studies in Turkey looked at the effect of different pick lacing arrangements with several shearer drums on the performance of longwall shearers.
In one trial, the researcher manufactured a drum that was incorporated into an Eickhoff EDW-230 double-ended ranging drum shearer and trialled underground (Tiryaki manufactured and welded some of the drums himself). The main change was a new pick lacing arrangement that took into account the circumferential pick spacing and single tracking concepts while keeping the other drum design and constructional parameters intact.
The original drum used a multi-tracking concept (more than one pick on the same cutting line), while the alternative developed was a single-tracking concept (employing one pick per cutting line). Sets of the two types of drums were tested in coal production under identical cutting conditions. Performance parameters such as pick consumption rate, shearer downtime, power consumption and vibrations were recorded during the trials.
The results proved that the improved drum’s lifespan increased by 70% in terms of total coal production, pick consumption rate decreased by 45% and cutting performance increased by up to 122%. The cutting energy required to excavate a unit amount of coal dropped by about 35% while shearer downtime decreased by 30%.
Dr Tiryaki argued excessive vibrations on shearers caused by drums are basically due to the fact that the circumferential pick spacing concept is not taken into consideration in shearer drum design.
Another key finding from the underground trials was that changing drum lacing from a triple-tracking to a single-tracking arrangement reduced dust and fines considerably. The studies found that shearer drums with multi-tracking tool arrangements generate considerable dust and fines, particularly when cutting a shallow depth of cut.
The studies also identified damage frequently occurring on the backplate of current shearer drums could be reduced by changing the lacing arrangement for the clearance ring (kerf) picks, rather than using costly wear-resistant materials.
Following this study, a computer program called the Vibration Analysis Program (VAP) was developed to evaluate vibrations and cutting efficiency for shearers, continuous miners and roadheaders.
In Australia, Dr Tiryaki aims to extend the software to the next level of complexity by utilising support from both ACARP (if funding is awarded) and several Australian longwalls for multi-site testing and finance.
Since being at CRC Mining, Dr Tiryaki has further developed the initial software into an enhanced program called Cutting Head Performance Analysis Software (CPAS) using MATLAB.
CPAS is able to check a drum design against excessive vibrations and inefficient cutting conditions by predicting the reaction forces and shaft torque acting on a drum, and power consumption and drawing its breakout pattern. Variations in reaction forces and shaft torque represent the vibration level while breakout pattern and power consumption are employed to evaluate the cutting efficiency.
With CPAS, the user prepares data files containing some details of shearer drum design before a particular computer analysis is carried out. Linear coal cutting tests using picks intended to be used on drums should also be performed to determine the coal cuttability parameters.
“The operational and some other design parameters can be entered in to the program using user interface controls on the simple and easy-to-use graphical user interface of the software,” Dr Tiryaki said.
Power consumption and vibration for example can be predicted for given coal cuttability, operational and drum design conditions. Changing these conditions allows any effects on shearer performance to be identified.
“The program can help design engineers to evaluate drum design in terms of cutting efficiency and machine vibrations before employing a particular drum in coal production operations,” Dr Tiryaki said.
“One of the aims of the CRC Mining Smart Longwalls Project is to improve the reliability of longwall mining components,” he said. “The software allows engineers to predict the vibration characteristics of the shearer drum before it is mounted on the shearer, preventing costly breakdowns, downtimes and repairs.
“I proposed a new project to ACARP on the measurement of forces on shearer ranging arms. In the course of this project, if accepted, I would like to measure the 3D reaction forces acting on the ranging arm depending on the coal seam conditions and design and operation of the shearer.
“I expect to improve the CPAS as software predicting the loads on shearer more accurately relying upon the outcomes of this project. The main problem is where to locate the sensors to measure the reaction forces correctly,” he said.
As part of the CRC Mining Smart Longwalls Project, Dr Tiryaki is hopeful of trialling a drum by late 2004.
Dr Tiryaki said the model behind the software could also be used to improve the design of cutting heads of roadheaders and continuous miners. Published in Australia's Longwalls, September edition.
