When a Mine is a Chemical Plant

When a Mine is a Chemical Plant
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Mining is a fascinating industry. There is something visceral about it – mother earth being uncovered in all her mineral beauty for us to harness – for many in the industry this raw appeal is like no other: it’s about rocks, minerals, their beauty and, of course, their value.

But mining is also about advanced chemical processing of minerals – chemical processes that are critical if a mineral’s value is to be realised and that demand a high level of process safety expertise in their operation.  Here we briefly explore some of the challenges faced by the mining industry at becoming good operators of these chemical processes and at adopting leading risk management practices from the chemical industry.

Mining Hazards From Upstream to Downstream

Core mining operations come with significant operational safety hazards, well known and understood by the industry, such as wall stability and falls of ground, heavy transportation by rail and haul truck, fire and explosion in underground mines and failures of tailings dams, amongst others. All of these have the potential to impact catastrophically upon a mining operation, both operationally, through injuries, fatalities, and damage to infrastructure and reputations.

These core mining hazards take their rightful place at the forefront of mining risk management, with the leading mining companies typically having a rich depth of experience in these areas, applying and advancing leading practice to reduce risk to acceptable levels, and with a subsequent high level of awareness and sensitivity to these issues amongst the workforce.

If we take the oil and gas analogy, these risks are associated with the ‘Upstream’ side of the mining operations. On the ‘Downstream’ side the risk profile of a mine operation changes substantially.

Enter the Chemical Plant

Gone are the visceral safety hazards associated with rocks, geology, gravity and mobile equipment, replaced by the process hazards of crushing and grinding, conveyors, and the advanced chemistries of mineral extraction and refining. As more advanced and chemically intensive mineral extraction techniques are employed, the downstream side of a mining operation increasingly takes on the hazard characteristics of a fully fledged chemical plant, where strong acids and bases are used, toxic reagents such as cyanide are employed, explosive atmospheres exist, and toxic gases like hydrogen sulphide can be liberated.

From experience at mine sites over the past 6 years, for leading operators, at leading mines throughout South America, Africa and Australia, it is common to see that the downstream process safety hazards – which in many cases can yield catastrophic impacts upon a mine operation – do not come with the same depth of expertise, the same focus on delivering leading risk management standards, or the same drive to reduce risks to ALARP, as with their upstream siblings.

Tolerance of Process Deviations

An hour in a chemical process control room at a mine commonly yields many substantial process safety management observations.  The following are some of the common areas of weakness:

  • Operating outside the original design limits of the process – running vessels, ponds and tanks above high or high-high set points.
  • Alarm flooding – where, by design – a control system will generate a significant number of low level ‘information’ alarms, such as for pump start and stop cycles. This flood will typcially cloud the important alarms.
  • Tolerance and blindness to the importance of alarms, including systems for detecting toxic gases or fire – the typical consequences of 1 and 2 above.
  • Lack of recording of and hand over protocols for critical events and alarms between shifts.
  • Low levels of competence around process operating procedures, with critical operating procedures difficult to access, or hard copies many years out of date.
  • Control rooms in low quality prefabricated buildings in close proximity to process plants, with little or no resilience during a major chemical incident or fire.
  • Lack of auditing and assurance focus – when was the last time the plant emergency shutdown procedure was practiced by the control room staff?

All of the above represent common contributory factors and lessons learned from many well-known oil, gas and chemical industry incidents. In certain regions, these chemical processes would attract substantial regulation under programmes like PSM (USA) and Seveso Directive (EU). In regions where such laws are not enacted or enforced and these plants are rolled up under mine concession agreements, drawn up and enforced my mine ministries, the regulation of the ‘chemical plant’ can be weak.

For a mine site that has no direct experience of a major chemical process plant incident, without strong regulation, and with a risk management team and line management who are typically more comfortable dealing with upstream mining hazards, the gaps in process safety risk management can remain unnoticed: a situation that has a high potential to result in painful surprises and hard lessons. A worst-case loss of a chemical process due to a major fire or explosion will shutter a mine operation for months.

Learning From the Process Industries

From a mining company perspective, there is much that can and needs to be done to advance risk management within these downstream chemical processes. The first is to seek leading practice from the major oil, gas and chemical companies: understand the basics and best practice; and then consider the following in the top 10 improvement actions, with an emphasis on getting it right in the process control room:

Ensure tight control over management of change – often, when a process is being run beyond its limits, it is the result of many little changes that have occurred over a prolonged period of time, or ‘creep’;

  1. Develop an operating culture where ‘we work within our process limits’ – operators should know not to use alarms as level indicators;
  2. Develop a knowledge base amongst the operators where they know absolutely the safe operating limits of their process;
  3. Apply performance indicators for alarm rates and other process indicators and treat and investigate critical alarms as substandard conditions;
  4. Eradicate simple language issues: the meaning of the acronym ‘LAHH’ that flashes on a control room operator’s screen is not immediately obvious unless you are good with English;
  5. Implement robust hand-over processes to record and communicate key process safety information between shifts, and how an operator should respond to process alarms when they occur;
  6. Condition operators to spot and deal with emergencies in a control room, and make this part of training, emergency plans and emergency drills;
  7. Refine process control systems, addressing alarm flooding issues, eradicating nuisance alarms and assigning levels of criticality so that the really important alarms stand out.
  8. Ensure that the mine site or wider corporate entity has the requisite in-house process safety engineering expertise, to advise on risk management technique and leading practice; and
  9. Ensure that chemical plant process control is subject to appropriate incisive, internal and external auditing.

It is clear that the leading mine operators do understand the potential impacts of their chemical operations – that is not disputed – however it is clear that on an industry wide scale this understanding is at a macro scale rather than in the process control room, where it needs to be. Many mine sites have yet to employ the same rigorous plant operating standards that, through many hard lessons, have become basic operating requirements for the leaders in the oil, gas and chemical industry sectors.