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            Success Story: Mining, Minerals, Metals

            Teck Cominco (Canada)

            Success Story: Mining, Minerals, Metals
             

            I. CUSTOMER ENVIRONMENT / PROJECT CONTEXT

             

            Customer profile:

            Teck Cominco's Highland Valley Copper (HVC) is a copper and molybdenum mine located 80km south-west of Kamloops, British Columbia. The mine is an open-pit truck-and-shovel operation employing conventional drill and blast mining methods. The mill has five grinding lines, implementing both semi-autogenous and autogeneous grinding and conventional flotation to produce metal concentrate from the ore. Concentrates are then transported by rail to customers throughout North America and exported via Vancouver to customers overseas.

             

            With the life of their mine recently extended to 2019, HVC needed to upgrade their facility-wide Bailey Infi-90 Distributed Control System (DCS). A new system would be required to manage all mill regulatory control – filtration, grinding (semi-auto/auto mills and ball mills), flotation, and concentration processes. The architecture was large – 1,100 analogue inputs, 350 analogue outputs, 900 digital inputs and 800 digital outputs with varying control strategies– from multi-constraint 3 tiered cascaded systems to simple single variable on-off control.

             

            Customer objective and constraints:

            In addition to the large amount of I/Os and the complex control strategies, HVC engineers had several other requirements for the new control system:

            •  Firstly, the control system had to be able to interface with the mill's existing CitectSCADA Human Machine Interface (HMI). It was also necessary that the vendor demonstrate a proven installed solution for implementing the new control system to the existing HMI.
            •  Secondly, the scan time for regulatory control loops had to be as fast as 100mS. Time sensitive calculations had to be based on real clock time and not scan time.
            •  Thirdly, the control system had to have flexibility in performing on-line configuration and programme changes. The system also had to allow for ‘Hot Swappable' modules such as I/O card swapping.
            •  Finally, the new control system platform had to be supplied from a stable, reputable vendor to ensure availability to new and inexpensive spare parts for years to come. It was also important that the programming software be IEC 61131-3 compliant.
             

            II. SOLUTION IMPLEMENTATION

             

            Implementation methodology (main phases):

            HVC migrated to a control system featuring Schneider Electric Modicon Quantum hot standby controllers, Unity Pro programming software, HART Interface Modules (HIMs), and Capstone Technologies process control software (Proportional-Integral-Derivative (PID) loop tuning/ optimising, gathering/analysing plant data). These combined technologies met the requirements of HVC.

             

            Unlike common DCS implementation solutions where the customer entrusts a single vendor, the HVC solution was provided by an integrator, distributor and manufacturer team.

            •  Fransen Engineering Ltd. integrated the solution by providing project management, system design, configuration, commissioning, and startup services.
            •  Guillevin International distributed the equipment.
            •  Schneider Electric manufactured the control hardware and provided training for the HVC engineers, instrument mechanics and other technical personnel.
            •  The new controls panels were fabricated by RIC Electronics Ltd. and installed by HVC's instrumentation department.
             

            Solution overview (services, products, systems, architectures...):

             

            • Hardware

            Innovative HART modules used in the installation perform three functions for the analogue I/O: they provide fused terminations in a compact footprint, allow the use of common standard analogue input and output modules and provide advanced HART interface capabilities. The modules form a distributed network of ethernet web servers allowing HVC engineers and asset management software remote access to maintenance information available in the connected valves, transmitters and other HART capable process control equipment.

             

            •  Software

            The Bailey Infi-90 control software was converted to an IEC 61131-3 compatible industrial control programme using Unity Pro programming software. Function Block Diagrams (FBD) and Sequential Function Charts (SFC) were employed to convert the Bailey programme. In order to simplify the conversion, object-oriented programming techniques were applied by developing application-specific Derived Function Blocks (DFB) and Derived Data Types (DDT).

             

            DFBs allow the programmer to develop a custom logic block that can represent an object such as a common control function or a physical piece of equipment. Example DFB representations are a PID controller function and Cyclone equipment. In addition to the standard features of a PID controller, such as feed forward and bump-less mode transfer, HVC had several other requirements for the PID DFB. Some of these requirements included process variable quality determination (i.e. bad signal, broken wire etc.) set point and controller output rate change limitation and derivative only on error. These functions as well as client specific advanced controls were implemented in the PID DFB. The cyclone DFB was implemented to control HVC's cyclones. Features such as total operating time and alarm information were easily added to this DFB. The features automatically replicate to each DFB instance.

             

            DDTs are pre-defined data structures that may be used to transfer data between DFBs and/or the HMI. A DDT standard was developed and used throughout the conversion process. Using DDT mitigated conversion errors streamlined the conversion process. An example of DDT power was to encapsulate loop data communicated between the controller and the CitectSCADA HMI. This resulted in a large amount of process data being available on the HMI with a small tag count.

             

            Variable animation tables were used extensively in the new Unity programme. Animation tables are user defined allowing them to be tailored to a specific application or function. HVC's animation tables allow them to modify analogue input, analogue output and PID configurations ‘on-the-fly' without the need for performing online builds. Use of these tables allows HVC to reconfigure an input channel's engineering span, lag filter time and/or linearisation specification. HVC may also temporarily place an analogue input channel (where process characteristics permit) into a maintenance mode where a ‘dummy' signal is temporarily used throughout the programme while the transmitter is being calibrated. The PID animation table allows HVC to modify tuning parameters, process variable span and controller output span ‘on-the-fly'.

             

            •  Testing and implementation

            "Downtime at a copper/molybdenum mine during this period of high commodity values is very expensive. To reduce risk and ensure a quick start-up, high importance was placed on testing and simulation of the new control software", says Kevin Borthwick, Senior Project Engineer, Fransen Engineering Ltd.

             

            Fransen Engineering Ltd. developed a complex process model of HVC's autogeneous and semi-autogeneous mills, ball mills, cyclones and flotation circuits. A multitude of constraints were included in the process model such as high hydrostatic limits, high power limits, valve characteristics, water ratios and process transport times. This model was interfaced via OPC to the new Quantum processors prior to installation. Process variables such as ore hardness, size and mill throughput were changed on the test unit to observe how the control system would react.

            This testing, performed at Fransen Engineering offices, ensured that the new control system would provide the regulatory control necessary to get the mill up and running within scheduled maintenance downtime when installed on-site. "This model helped ensure a seamless startup" says the Instrumentation Foreman, Highland Valley Copper.

            Solution overview (services, products, systems, architectures...):
             

            III. RESULTS / ACHIEVEMENT

             

            Customer benefits:

            This new control system gives the HVC site a single architecture for their entire control system. The hot standby architecture maximises facility uptime while the open platform supports advanced features such as asset management systems and process optimisation. Spare parts inventory has been reduced and ongoing training costs minimised. Moreover, HVC enjoys cross functional support from their electrical and instrumentation departments for the new control architecture.

             

            Customer testimonies (Verbatim):

            Senior Process Control Engineer at Highland Valley Copper:

             

            "HVC selected this solution because we were pleased with the high level of reliability of the existing mill electrical department control equipment provided by Schneider Electric's Quantum PLCs, Concept programming software, and CitectSCADA HMI software. Also, Fransen Engineering has a proven track record of implementing DCS upgrades of similar size and scope" 

             
             
             
             
             

            Key downloads & links

             

            Solution breakdown

            •  Process Control: Modicon Quantum HSBY PLCs
            •  Unity Pro programming software
            •  HART Interface Module (HMI)