Operate digestion equipment

This unit of competency covers the skills and knowledge needed to operate typical digestion equipment as used in a metalliferous minerals processing plant. It also includes solving problems with digestion processes and equipment.


This unit applies to a person who has the responsibility for starting up and shutting down digestion equipment to procedures; and making adjustments to flow rate, pressure and temperature, depending on the type of digestion equipment.

This unit applies to an individual working alone or as part of a team or group and working in liaison with other shift team members and the control room operator, as appropriate.

This unit does not cover leaching equipment, which is instead covered by:

PMAOPS263A Operate leaching equipment.


Not applicable.

Elements and Performance Criteria


Prepare for work


Identify work requirements


Identify and control hazards


Coordinate with appropriate personnel


Check for recent work undertaken on plant


Note any outstanding/incomplete work


Check operational status of digestion plant/equipment


Complete any required pre-start checks


Operate digestion equipment


Identify the type of digestion equipment


Start up and shut down digestion equipment according to the digestion equipment type and duty


Adjust flow, temperature and pressure as appropriate to type of digestion equipment


Complete routine checks, logs and paperwork, taking appropriate action on unexpected readings and trends


Recognise problems and take appropriate action


Monitor plant frequently and critically throughout shift using measured/indicated data and senses (e.g. sight and hearing), as appropriate


Recognise developing situations which may require action


Make appropriate adjustments to digestion equipment and duty


Take other appropriate actions on digestion problems, as required


Identify upstream and downstream impacts of any adjustment made or variation in conditions


Isolate and de-isolate plant


Isolate plant


Make safe for required work


Check plant is ready to be returned to service


Prepare plant for return to service

Required Skills

Required skills

Required skills include:

efficient and effective operation of plant/equipment

recognising conditions which will lead to out of specification operation

implementing enterprise procedures within time constraints and in a manner relevant to the correct use of the equipment

conveying information relevant to the operation clearly and effectively

maintaining appropriate levels of quality assurance

reading and numeracy to interpret workplace documents and technical information

Required knowledge

Required knowledge of digestion equipment principles and typical problems, to a level needed to control the operation, includes:

principles of operation of digestion plant/equipment

process parameters and limits (e.g. temperature, pressure, flow and pH)

duty of care obligations

hierarchy of control

communication protocols (e.g. radio, phone, computer, paper and permissions/authorities)

typical issues causing problems and the resolution of those problems

routine problems, faults and their symptoms and the corrective action to be taken

relevant alarms and actions

plant process idiosyncrasies

all items on a schematic of the plant item and the function/principles of operation, and problem solving of each

physics and chemistry relevant to each unit and the processes used

function and troubleshooting of major internal components and their problems, such as internals, supports, pumps or agitators

relevant environmental and heritage requirements

pressure relief systems (e.g. valves and rupture discs)

containment systems


Evidence Required

The evidence guide provides advice on assessment and must be read in conjunction with the performance criteria required skills and knowledge range statement and the Assessment Guidelines for the Training Package.

Critical aspects for assessment and evidence required to demonstrate competency in this unit

Critical aspects for assessment and evidence are:

early warning signs of equipment/processes needing attention or with potential problems are recognised

the range of possible causes can be identified and analysed and the most likely cause determined

appropriate action is taken to ensure a timely return to full performance

obvious problems in related plant areas are recognised and an appropriate contribution made to their solution.

Context of and specific resources for assessment

Assessment of this competency will occur over a range of situations which will include typical disruptions to normal, smooth operation. This will require access to an operating plant over an extended period of time, or a suitable method of gathering evidence of operating ability. Where safety, lack of opportunity or significant cost is an issue an industry-based simulation may be employed to assist the process.

Guidance information for assessment

Assessment processes and techniques must be appropriate to the language, competency and safety requirements of the site and consistent with workplace systems or procedures.

Range Statement

The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording, if used in the performance criteria, is detailed below. Essential operating conditions that may be present with training and assessment (depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts) may also be included.


This competency includes all types of digestion equipment, including but not limited to:

autoclave digesters

tube digesters


Procedures may be written, verbal, computer-based or in some other form. They may include, but are not limited to:

all work instructions

standard operating procedures


batch sheets

temporary instructions

any similar instructions provided for the smooth running of the plant

good operating practice as may be defined by industry codes of practice

Procedures would be expected to comply with any relevant government regulations.

Logs and reports

Logs and reports may include:

paper or electronic-based logs and reports

verbal/radio reports

reporting items found which require action

Appropriate action

Appropriate action includes, but is not limited to:

determining problems needing action

accessing and applying relevant technical and plant data

applying appropriate problem solving techniques to determine possible fault causes

rectifying problem using appropriate solution within area of responsibility

following through items initiated until final resolution has occurred

reporting problems outside area of responsibility/ability to designated person

Typical problems

Typical problems may include, but are not limited to:

seal/gasket leaks

pressure loss/low flow

high pressure



driver problems

temperature excursions (high or low)

Remedial actions

Remedial actions may include, but are not limited to:

making adjustments to the equipment (flow, pressure, etc)

carrying out minor maintenance within operator's skill level

identifying and reporting problems outside operator's scope of ability

identifying and controlling hazards related to digestion equipment and surrounding areas

Start up and shut down as required

Start up and shut down as required includes:

start up and shut down to/from normal operating conditions

start up and shut down to/from isolated, cold or empty

all other conditions experienced on the plant (i.e. from any condition to any condition experienced on the plant)

Health, safety and environment (HSE)

All operations to which this unit applies are subject to stringent HSE requirements, which may be imposed through state or federal legislation, and these must not be compromised at any time. Where there is an apparent conflict between Performance Criteria and HSE requirements, the HSE requirements take precedence.

Work requirements

Work requirements may come from briefings, handovers and work orders and may include:

compliance documentation

product specifications

nature and scope of tasks

achievement targets

operational conditions

lighting conditions

plant or equipment defects

hazards and potential hazards

coordination requirements or issues



Unit sector

Employability Skills

This unit contains employability skills.

Licensing Information

Not applicable.