Elements and Performance Criteria

This competency unit includes the mixing of asphalt using a range of pug and drum mixers and for a range of purposes. It is intended to apply to batching plants as used by the asphalt industry and may cover batch, continuous, fixed and mobile plants.
Aggregate may include the normal range of gravels and sand as well as RAP (recycled asphalt pavement). It may, or may not, include the addition of special aggregates such as slag, carborundum, lime or crushed garnets.
It covers both the use of natural bitumen such as is obtained from oil refineries and also synthetic bitumen used for coloured asphalt.

Context
Typical problems include -
equipment malfunction
raw material specifications
mixing tolerance
uniform dispersion of minor ingredients/additives
mixing to special requirements
matching mixes produced with production requirements
adjusting mix formula to compensate for variations in raw materials (eg, aggregate moisture content).
This competency includes the operation of all ancillary equipment and the operation of plant using PLCs where appropriate.
All operations are performed in accordance with standard procedures and work instructions.

Essential knowledge and enterprise requirements
Knowledge and understanding of the equipment sufficient to recognise potential problems and to take appropriate action.
Knowledge of the enterprise's standard procedures and work instructions and relevant regulatory requirements along with the ability to implement them within appropriate time constraints and in a manner relevant to the operation of the equipment.

Competence includes the ability to:


apply and/or describe:

principles of drying of aggregates
principles of mixing these products
impact of variations in raw materials on final product
impact of mixing on final product
enterprise production schedules

distinguish between causes of faults such as:

raw material
equipment
mixing time/technique
as is relevant to the practical operation of the equipment.

Critical aspects
It is essential that the equipment be understood and that the importance of critical material properties and mixing variables is known. Competence must be demonstrated in the ability to recognise and analyse potential situations requiring action and then in implementing appropriate corrective action.

Consistent performance should be demonstrated. In particular look to see that:

product is produced on time and in specification
upstream and downstream communication is timely and effective
problems are anticipated and appropriate action is taken (ie, problem fixed or reported).
Competence must be demonstrated in the operation of all ancillary equipment to the level required for this competency unit.

Concurrent assessment and prerequisite competencies

This unit may be assessed in conjunction with:

PMCSUP180A Organise self
PMCSUP181A Work in a team.
Individual enterprises may choose to add prerequisites and corequisites relevant to their processes. In remote operations, this person may also need scheduling and other materials ordering and handling competencies.

Assessment method, context and resource implications
Competence in this unit may be assessed by observation over time on an operating plant. Where this is done, the timeframe must allow for adequate assessment of operation under all normal and a range of abnormal conditions. Where this is not practical, additional assessment techniques must be used.
Competence may also be assessed by use of a suitable simulation and/or a range of case studies/scenarios. A combination of these techniques should be used to ensure the competency is adequately assessed.
In all cases it is expected that the practical assessment will be supported by targeted questioning to assess the underpinning knowledge. Questioning will be undertaken in such a manner as is appropriate to the language and literacy levels of the operator and reflecting the requirements of the competency.
Resources required include suitable access to an operating plant or equipment which allows for appropriate and realistic simulation. A bank of case studies/scenarios will also be required where these form part of the assessment method. Questioning may take place either in the workplace, or in an adjacent, quiet facility such as an office or lunch room. No other special resources are required.

Communicating ideas and information
(1)

Collecting analysing and organising information
(2)

Planning and organising activities
(2)

Working with others and in teams
(2)

Using mathematical ideas and techniques
(1)

Solving problems
(1)

Using technology
(1)