This project was the beginning of a series of design and build tasks focused on creating a comprehensive set of maintenance and repair tooling for the HPGR unit at Penasquito Mine. The majority of the tooling projects were designed to simplify maintenance of the HPGR rollers and allow the rollers to actually be completely refurbished in-house at a new machine shop facility. I was responsible for all engineering calculations and designs for this project and also supervised the entire fabrication process.
The scope of this project was to design and build a heavy-duty turntable that could support and precisely rotate the HPGR roller during maintenance operations. Once the HPGR roller had been removed from the main HPGR unit and transported to the machine shop, it was placed end-up on the turntable with its vertical axis perpendicular to the table face. The customer requirement for the table was that it allow the roller to be secured while the mounting axle was removed from the center of the roller. This operation required that the roller be slowly rotated while maintenance personnel pneumatically hammered and pried the axle evenly out of the roller.
For this project, I designed a round steel base-table capable of supporting the 50-ton load of the HPGR roller and a multi-layer steel ring assembly that floated on the top of the table. All components were designed to supported and interface with an inner bearing, allowing free-rotation between the rings and table. The turntable was a gear driven assembly and I designed the gear ratio to favorably match the torque characteristics of the selected driver motor. One level of the steel ring assembly was designed to have custom cut gear teeth that interlock with the pinion gear of the driver motor. To maintain economical pricing for the customer, I selected pre-manufactured parts wherever possible, including a Caterpillar excavator-cab bearing, the electric motor, transmission, and pinion gear.
Throughout the project, I performed all engineering stress calculations to assure table and bearing structural stability during loading operations. Additionally, I was responsible for all electrical and control design, which included a central control panel that controlled the driver motor using a variable frequency drive.