Ok Tedi Automation Roadmap
Sector: Mining
- Papua New Guinea
Project overview
Between 2018 and 2020, the Mipac team worked in close collaboration with Ok Tedi Mining Limited (OTML) to improve their operations and automate their systems to achieve optimal operational efficiency through digital maturity. This work contributed to OTML’s strategic goal of improving their process automation and reducing production loss due to lack of automation.
The client
Ok Tedi, established in 1981, was previously run by BHP until the mine nationalised in 2013. It is 100% owned and run by the people of PNG, with 67% owned by the PNG government and 33% owned by a consortium of the local landowners.
Ok Tedi is the longest running mine in PNG, located in the Star Mountains, just 16kms from the border with Indonesia. It produces copper, gold and silver, mining 240kt of overburden and 60kt of ore daily, at an annual rate of 24Mtpa.
Background
In 2018, OTML was experiencing plant instability and wanted to reduce variability from its operations. Gold and copper recovery was low, plant equipment was unreliable and, as a result, operators were running the plant in manual. A lack of digital maturity meant that the site was not ready to implement desired business improvement projects. Mipac was engaged to support the site through the co-development of a three-year automation roadmap (see Figure 1) and delivery of related projects.
Scope
Under the umbrella of the three-year automation roadmap, Mipac worked with Ok Tedi to target three key areas of concern:
- Instrumentation and process control optimisation to provide the basis for increasing process stability
- Data and business intelligence to improve decision making for the plant based on real data and analysis, shown by the short time interval control
- Capability development and support to ensure the gains in the other two prongs could be realised and have legacy long after the implementation team was finished
Project case studies
Hydrocyclones (Optimisation)
Problem:
Hydrocyclones blocking, causing downtime
Solution:
- Automate sump and hydrocyclone control
- Monitor and report percentage of time in automatic control
Outcome:
Reduction in hydrocyclone blocking and downtime events
Flotation (Process control)
Problem:
Poor flotation cell level control, resulting in loss of recovery
Solution:
Implement feed-forward control to stabilise and improve level control
Outcome:
Improved level control, resulting in more consistent froth recovery, mass pull and concentrate grade
Business intelligence via MPA (Data and business intelligence)
Problem:
Limited visibility and transparency of underperformance reasons
Solution:
Automated real-time reporting of performance and restraints
Outcome:
Increased accountability and performance
Project challenges
Whilst COVID-19 prohibited travel to site and forced 100% remote delivery for parts of this project, the use of Mipac’s Confluence portal enabled the site to have reasonable contact with the Mipac team and continue to log requests. The portal also enabled the transfer of knowledge to ensure the project could continue and improvements could be rolled out.
“The milling circuit was a real bottleneck of Ok Tedi’s operations and a particular challenge that operators were facing was the bogging of the cyclone system. To address this, we applied some automation and control around cyclone feed sump and cyclone operation to prevent those downtime events from occurring, as well as conditioning the feed so it was suitable and optimised for downstream flotation. The design of this control philosophy was expected to deliver up to $2 million dollars per annum in benefits to Ok Tedi.”
Project outcomes
The delivery of OTML’s automation roadmap, together with related projects, resulted in:
- Increased gold recovery from 55 – 70% and increased copper recovery from 83 – 89%
- Enhanced digital maturity
- A stable, automated operation (enhanced by the operation’s new levels of digital maturity) which has created time for other site improvements
Mipac: What were the contributing factors for the success of this project?
Lyndah Brown, OTML: They (Mipac) listened to what we wanted and tailored the project within our boundaries and team capabilities. We utilised their experience in project management and their project management portal, Confluence, to assist us with any support we needed, whether it be operational support or project management. This portal allowed us to track the values of the different projects we were putting in place; it also enabled us to capture what changes have been implemented and the knowledge that goes with that. That means that if one of our team leaves, the knowledge remains and there is a continuity for the next team to build on.
