List the assessment methods to be used and the context and resources required for assessment. Copy and paste the relevant sections from the evidence guide below and then re-write these in plain English.
Elements describe the essential outcomes. | Performance criteria describe the performance needed to demonstrate achievement of the element. |
1 | Classify ore samples and select fluxing method | 1.1 | Review client request to identify sample/analysis requirements, preparation methods and equipment involved |
| 1.2 | Inspect samples, compare with specifications, record and report any discrepancies |
| 1.3 | Conduct visual and simple chemical tests to identify the type of sample and sulphide concentrations |
| 1.4 | Review client sample/analysis history and identify possible chemical interferences |
| 1.5 | Decide whether non-standard fluxing is required |
| 1.6 | Select sample weight and flux to optimise precious metal recovery and purity |
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2 | Prepare for precious metal recovery | 2.1 | Identify hazards and workplace safety procedures associated with the sample, preparation methods, reagents and equipment |
| 2.2 | Examine the recommended preparation method to identify the critical steps that will affect the quality of analytical results |
| 2.3 | Plan parallel work sequences to optimise the throughput of multiple sets of samples |
| 2.4 | Assemble all required equipments, materials, reagents and check they are fit for purpose |
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3 | Recover precious metals from ore sample | 3.1 | Weigh required amounts of sample and flux components to achieve an acceptable button and fluid slag |
| 3.2 | Select the type and size of pot to suit sample method and client requirements |
| 3.3 | Mix charge to ensure homogeneity and optimal collection of precious metal |
| 3.4 | Set and monitor furnace temperature/time to ensure complete fusion |
| 3.5 | Separate slag and button with minimal loss of lead collector |
| 3.6 | Maintain sequencing in order to track samples, buttons and prills throughout the recovery process |
| 3.7 | Separate lead collector from the required precious metal and check for contamination, losses and evidence of other precious metals |
| 3.8 | Minimise personal exposure to hazards and the release of collectors to the work environment |
| 3.9 | Collate laboratory documentation and the prepared sample and present for analysis |
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4 | Troubleshoot and correct failed recovery | 4.1 | Monitor all stages of recovery for indicators of potential loss |
| 4.2 | Recognise undesirable recovery conditions and decide whether the process requires correction |
| 4.3 | Choose an appropriate corrective action and re-start the process |
| 4.4 | Document any adjustments made to standard methods and re-sequencing of samples |
| 4.5 | Seek advice when problems are beyond scope of responsibility or knowledge |
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5 | Perform daily maintenance of assay equipment | 5.1 | Segregate and dispose of waste in accordance with workplace requirements |
| 5.2 | Grade and inspect pots using established criteria prior to storage for re-use |
| 5.3 | Inspect furnaces for cracks, unserviceable components and remove slag |
| 5.4 | Inspect and clean extractive systems |
| 5.5 | Report defective equipment and consumable requirements to appropriate personnel |
Evidence of competence in this unit must satisfy all of the requirements of the elements and performance criteria, and include demonstration of:
safely performing fire assay techniques to extract a range of precious metals from their host matrices in readiness for analysis on at least three (3) occasions
interpreting and closely following standard recovery methods
selecting and modifying laboratory methods to suit particular ores and to ensure total recovery
accurately weighing samples and flux components
maintaining close attention to technical and safety requirements in a physically demanding hazardous environment
maintaining sequential control of samples through all recovery stages
optimising work flow to ensure efficiency of recovery for multiple client samples
recognising and identifying the cause of non-acceptable received and fused samples, buttons and prills
identifying indicators of poor recovery and contamination
applying knowledge of mineral chemistry and fire assay techniques to solve recovery and contamination problems
keeping accurate and complete records, including:
pour sheets (date, time, client, pour number and preparation method)
number of pots, positions of sample, blank and check in rack
adjustments made to standard preparation methods for specific samples
analytical method
assay data
minimising rework, waste and environmental impacts
safely collecting and disposing of all waste responsibly
recognising hazards, using workplace safety procedures and safety equipment to work safely at all times.
Must provide evidence that demonstrates knowledge of:
chemical and physical principles relating to:
fusion of mineral ores
cupellation
parting and digestion processes
expected physical and chemical properties of materials at each recovery stage
standard methods for the fire assay of a range of precious metal ores relevant to job role
criteria for an 'acceptable' button, including:
one piece, mass >20g and <50g
malleable
separates cleanly from slag
free of undecomposed ore, matte and speiss
causes of contamination, including:
poorly made cupels
base metals (copper (Cu), nickel (Ni), zinc (Zn) and bismuth (Bi))
arsenic (As), sulphur (S), antimony (Sb), selenium (Se), tellurium (Te) and chromium (Cr)
scoria
sprouting
indicators of potential loss and the corrective actions, including:
viscous slag (check furnace temperature, adjust flux and lower charge weight)
lead shotting (adjust flux and lower charge weight to compensate for high oxides, silicates and chromites)
sulphides (adjust fusion time and adjust sample weight and/or flux)
matte, speiss (adjust sample weight and flux)
incomplete fusion (adjust sample weight and/or flux)
unacceptable button (adjust sample weight and/or flux)
inquartation (add 3 parts silver (Ag) to prill, wrap in lead foil and re-cupel)
workplace safety procedures and operation of safety equipment
function and operation of assay/equipment used as part of job role
workplace and/or legal traceability requirements
relevant hazards, work health and safety (WHS) and environment requirements.
Judgment of competence must be based on holistic assessment of the evidence. Assessment methods must confirm consistency of performance over time, rather than a single assessment event.
This unit of competency is to be assessed in the workplace or a simulated workplace environment. A simulated workplace environment must reflect realistic operational workplace conditions that cover all aspects of workplace performance, including the environment, task skills, task management skills, contingency management skills and job role environment skills.
Foundation skills are integral to competent performance of the unit and should not be assessed separately.
Assessment processes and techniques must be appropriate to the language, literacy and numeracy requirements of the work being performed and the needs of the candidate.
Knowledge evidence may be collected concurrently with performance evidence or through an independent process, such as workbooks, written assessments or interviews (provided a record is kept in each case).
This unit of competency may be assessed with:
MSL975020 Apply routine spectrometric techniques
Holistic assessment methods include:
observation of the candidate
review of quality control performance and analytical results traceable to assay samples prepared by the candidate
review of sample records prepared by the candidate
feedback from supervisors, peers and/or clients about the candidate’s ability to safely and efficiently extract a range of precious metals from their host matrices in readiness for analysis, provide acceptable buttons and prills, and troubleshoot and correct common recovery failures
written/oral questioning about relevant mineral chemistry principles, precious metal recovery steps, typical problems and corrective actions.
Access is required to instruments, equipment, materials, workplace documentation, procedures and specifications associated with this unit, including, but not limited to:
client requests/documentation, including client profile, sample identification, sample receipt, storage and analyses, and required preparation method/and service charges
a variety of precious metal ore samples
fire assay methods, examples of assay records, equipment, materials and reagents
assay equipment, including:
mixing equipment and balances
fusion and muffle furnaces and associated spares
temperature sensors and hotplates
compressed air service, extraction systems and fuel supply lines
pots, cupels, pouring equipment, pot loader, trolleys, moulds, tongs and hammers
safety equipment and workplace safety procedures.
Assessors must satisfy the assessor competency requirements that are in place at the time of the assessment as set by the VET regulator.
The assessor must demonstrate both technical competence and currency.
Technical competence can be demonstrated through:
relevant VET or other qualification/Statement of Attainment AND/OR
relevant workplace experience.
Currency can be demonstrated through:
performing the competency being assessed as part of current employment OR
having consulted with a laboratory about performing the competency being assessed within the last twelve months.