Elements and Performance Criteria

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.
Codes of practice
Where reference is made to industry codes of practice, and/or Australian/international standards, it is expected the latest version will be used
Standards, codes, procedures and/or enterprise requirements
Standards, codes, procedures and/or enterprise requirements may include:
Australian and international standards, such as:
AS 3988-1991 Copper, lead, zinc, gold and silver ores - Guide to sample preparation for the determination of gold
AS 3895.1-1991 Methods for the analysis of copper, lead, zinc, gold and silver ores - Determination of gold (Fire assay-Flame AAS method)
AS ISO 17025-2005 General requirements for the competence of testing and calibration laboratories
AS/NZS ISO 14000 Set:2005 Environmental management standards set
AS/NZS ISO 9000 Set:2008 Quality management systems set
calibration and maintenance schedules
enterprise recording and reporting procedures
enterprise sampling procedures for specific samples, sites and clients
environmental legislation and regulations
equipment manuals and warranties, supplier catalogues and handbooks
equipment startup, operation and shutdown procedures
industry codes of practice
material safety data sheets (MSDS)
occupational health and safety (OHS) national standards and codes of practice
principles of good laboratory practice (GLP)
production and laboratory schedules
quality manuals, training manuals and induction manuals
standard operating procedures (SOPs) and published preparation methods
Samples
Samples may include:
solids, such as rocks, minerals, soils, sands and stream sediments
core and other drill samples (rotary air blast (RAB), reverse circulation (RC) and aircore)
slurries, powder concentrates and metallurgical solutions
dump samples and grab samples
Client requests/documentation
Client requests/documentation may include:
client profile, sample identification, sample receipt, storage and analyses
required preparation method/and service charges
Assay equipment
Assay equipment may include:
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
Hazards
Hazards may include:
dust, silica, slag, glass shards and molten flux
chemicals, such as hydrofluoric acid, bromine, perchloric acid, aqua regia, cyanide, lead-based compounds, free-mercury and nickel compounds
noise and vibration
crushing, entanglement and cuts associated with moving machinery
manual handling of heavy loads, such as pots, racks and trolleys
heat exhaustion/stress and fatigue
Safety equipment and procedures
Safety equipment and procedures may include:
ensuring access to service shut-off points, fire extinguishers/fire hose, safety shower/eye wash stations and first aid station
recognising and observing hazard warnings and safety signs
labelling of samples, reagents and hazardous materials
direct extraction and fumehoods
guards for moving machinery parts
noise insulation
using personal protective equipment, such as dust masks, heat resistant mittens, safety face shields with tinted visor, coats, ear muffs, safety boots, heat reflective clothing and latex gloves for flux handling
following established manual handling procedures
regular cleaning of equipment and work areas using enterprise procedures
reporting of abnormal emissions, discharges and airborne contaminants, such as noise, light, solids, liquids, water/waste water, gasses, smoke, vapour, fumes, odour and particulars to appropriate personnel
Fluxes
Fluxes may include:
bulk fluxes containing PbO, borax, soda ash, silica, silver nitrate and flour
non-standard flux additives:
flour (oxidising samples)
nitre (reducing samples, sulphides)
silica (basic ores)
PbO (siliceous ores)
exotic additives, such as CaF2 (refractory ores)
NiS (NiCO3, sulphur, borax and soda ash)
Pots
Pots may include:
ceramic, acidic/basic, alumina, zirconia and graphite
Sequencing of pots in a rack
Sequencing of pots in a rack may include:
addition of silver wire
addition of coloured salts (e.g. copper (Cu))
position of reagent blanks, standards, check samples
Collectors
Collectors may include:
lead (Pb), nickel sulphide (NiS), bismuth (Bi) and tin (Sn)
Criteria for an 'acceptable' button
Criteria for an 'acceptable' button could include:
one piece, mass >20g and <50g
malleable
separates cleanly from slag
free of undecomposed ore, matte and speiss
Separation of collectors
Separation of collectors may include:
cupellation
digestion
parting, annealing and weighing for a gravimetric finish
Contamination
Contamination may be caused by:
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
Documentation
Documentation may include:
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
Indicators of potential loss and the corrective action
Indicators of potential loss and the corrective action may include:
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
Waste
Waste may include:
rejected pots and cupels
slag and furnace material
disposable personal protective equipment
Occupational health and safety (OHS) and environmental management requirements
OHS and environmental management requirements:
all operations must comply with enterprise OHS and environmental management requirements, which may be imposed through state/territory or federal legislation - these requirements must not be compromised at any time
all operations assume the potentially hazardous nature of samples and require standard precautions to be applied
where relevant, users should access and apply current industry understanding of infection control issued by the National Health and Medical Research Council (NHMRC) and State and Territory Departments of Health

EVIDENCE GUIDE
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.

Overview of assessment

Critical aspects for assessment and evidence required to demonstrate competency in this unit
Assessors should ensure that candidates can:
recognise hazards and work safely at all times
interpret, follow and adjust (as necessary) standard recovery methods
maintain close attention to technical and safety requirements in a physically demanding/hazardous environment
maintain sequential control of samples through all recovery stages
optimise work flow to ensure efficiency of recovery for multiple client samples
identify indicators of poor recovery
apply a knowledge of mineral chemistry and fire assay techniques to select and implement logical corrective actions to improve recovery rates
minimise rework, waste and environmental impacts
dispose of all waste responsibly.

Context of and specific resources for assessment
This unit of competency is to be assessed in the workplace or simulated workplace environment.
This unit of competency may be assessed with:
MSL975020A Apply routine spectrometric techniques.
Resources may include:
a variety of precious metal ore samples
fire assay methods
fire assay equipment, materials and reagents
safety equipment.

Method of assessment
The following assessment methods are suggested:
review of quality control performance and analytical results traceable to assay samples prepared by the candidate
review of workplace documentation prepared by the candidate
feedback from peers, clients and supervisors
written/oral questioning about precious metal recovery steps, typical problems and corrective actions.
In all cases, practical assessment should be supported by questions to assess underpinning knowledge and those aspects of competency which are difficult to assess directly.
Where applicable, reasonable adjustment must be made to work environments and training situations to accommodate ethnicity, age, gender, demographics and disability.
Access must be provided to appropriate learning and/or assessment support when required.
The language, literacy and numeracy demands of assessment should not be greater than those required to undertake the unit of competency in a work like environment.

This competency in practice
Industry representatives have provided the case study below to illustrate the practical application of this unit of competency and show its relevance in a workplace setting.
Mineral processing
A fire pourer has noticed a large amount of fine lead shot in the bottom of a pot and seeks advice from the fire assayer. The assayer examines the pot closely and notices a lime green slag colour on the inside of the pot and on the lead button. He/she identifies this as a possible 'chromite' problem and explains that the darker the lime green colour is, the higher the chromium contamination. He/she explains to the pourer that there are two ways of dealing with this problem. The first is to reduce the sample weight to ~5g (for >10% chromite) or to develop its own special flux that has low litharge and silica to ensure that the sample is properly reduced. Because there is no history of regular chromite problems with this particular client's samples, he/she decides that a special flux is not warranted and tells the pourer to reduce the charge weight and to ensure that the components are very well mixed. He/she gives the pourer clear instructions for conducting the repeat assay and documents how the sample was treated.