MSL973011A
Perform fire pouring techniques

This unit of competency covers the ability to follow standard procedures for extracting precious metals from their host matrices in readiness for analysis. Fire pourers are expected to handle routine samples, recognise common sample preparation and cupellation problems and make standard adjustments to fluxes and firings. They are expected to seek advice from their supervisor when non-routine problems arise.

Application

This unit of competency is applicable to laboratory personnel working in the mineral assay industry sector.

Industry representatives have provided case studies to illustrate the practical application of this unit of competency and to show its relevance in a workplace setting. These can be found at the end of this unit of competency under the section 'This competency in practice'.


Elements and Performance Criteria

ELEMENT

PERFORMANCE CRITERIA

1. Plan work for shift

1.1. Review job requests to identify the samples, preparation methods required for each and shift priorities

1.2. Identify hazards, safety equipment/procedures associated with samples, preparation methods, reagents and equipment

1.3. Plan parallel work sequences to optimise the throughput of multiple sets of samples during shift

1.4. Assemble all required equipment, materials, reagents and check they are fit for purpose

1.5. Check pots/cupels and discard those with faults and/or a record of high gold values

1.6. Check that fusion and muffle furnaces are operating at the specified temperatures

2. Prepare sample racks for fusion

2.1. Check samples against accompanying documentation and record/report any discrepancies

2.2. Conduct simple visual/chemical tests for each sample to assess the adequacy of prior sample preparation and possible presence of sulphides or other mineralogy

2.3. Weigh out the recommended amount of sample and add specified identifier to maintain orientation, as necessary

2.4. Weigh out flux components, mix thoroughly with the sample charge and transfer to recommended type/size of pot without loss of material

2.5. Place pots in racks

2.6. Record all required details of sample preparation to ensure traceability of samples

2.7. Seek advice to deal with any situation beyond scope of responsibility or knowledge

3. Obtain acceptable buttons and prills

3.1. Maintain sequencing in order to track samples, buttons and prills throughout the recovery process

3.2. Monitor furnace temperature/time to ensure complete sample fusion

3.3. Remove fused samples from furnace and pour into moulds with minimal loss of material

3.4. Recognise the need for repeat firings due to lead shotting and/or poor fusions

3.5. Separate slag and button with minimal loss of collector

3.6. Inspect buttons for matte, brittleness, size and malformed shape

3.7. Place acceptable buttons in muffle furnace using cupels that have been previously loaded and preheated

3.8. Regularly monitor furnace temperature/time/air flow to ensure efficient cupellation

3.9. Recover prills, check identifiers and inspect for contamination, losses and evidence of other precious metals

3.10. Complete and collate sample records before presenting prills for analysis

4. Troubleshoot and correct common recovery failures

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. Apply an established corrective action and restart 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

5. Perform daily maintenance of assay equipment

5.1. Grade and inspect pots using established criteria prior to storage for re-use

5.2. Report defective equipment and consumable requirements to appropriate personnel

6. Maintain a safe work environment

6.1. Use safe work procedures and protective equipment to ensure personal safety and that of others

6.2. Minimise the release of collectors to the work environment

6.3. Segregate and dispose of wastes in accordance with enterprise requirements

Required Skills

Required skills

Required skills include:

accurately weighing samples and flux components

manual handling of heavy/hot items of equipment

hand-eye coordination during pouring and knocking up buttons

recognising non-acceptable characteristics of received and fused samples, buttons and prills

applying standard methods and procedures and approved variations

Required knowledge

Required knowledge includes:

procedures for:

fusion of common mineral oresamples

cupellation of buttons

digestion/partingof prills

function, operation and maintenance of assay equipment

hazards, control measures, operation and maintenance of safety equipment

enterprise and/or legal traceability requirementsrelevant to job role

health, safety and environment requirements relevant to job role

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.

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 and follow 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

plan work flow to ensure efficient sample throughput

recognise indicators of poor recovery and apply established corrective actions

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:

MSL953001A Receive and prepare samples for testing

MSL943002A Participate in laboratory/field workplace safety.

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 sample records prepared by the candidate

feedback from peers, clients and supervisors

written/oral questioning about fire pouring techniques, 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 laboratory routinely determines the 'total' gold concentration of its clients' samples. A technician is preparing a rack of samples for the day's first pour. He/she monitors the furnace temperature and assembles the necessary pots, cupels and other equipment. He/she checks the client's specifications for the first sample and notices that it is dark grey. The technician recognises that this colour often indicates a high sulphide content and follows the established procedure for adjusting the flux recipe and sample charge weight to compensate. He/she carefully mixes the sample and flux and places the pot in the rack, carefully noting its position. The technician prepares the remaining samples, blanks, and check samples according to requirements. A satisfactory fusion and pour is obtained for all samples except for one that shows some 'lead shotting'. The technician adjusts the flux and sample charge weight and repeats the process. The repeat sample provides an acceptable button. He/she cupels the button to separate the precious metal from the first collector (lead). The prill is placed in a numbered container for subsequent digestion and analysis by atomic absorption spectroscopy (AAS).


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 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 warranty, 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, 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 (e.g. 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

Consideration of mineralogy

Consideration of mineralogy may include:

recognising presence of highly oxidised ores, such as haematite or magnetite

adjusting charge weight and flux components to suit

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 fume hoods

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 particulates to appropriate personnel

Fluxes

Fluxes may include:

bulk fluxes containing lead (II) oxide (PbO), borax, soda ash, silica, silver nitrate and flour

non-standard flux additives, such as:

flour (oxidising samples)

potassium nitrate (reducing samples and sulphides)

silica (basic ores)

lead as PbO (siliceous ores)

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 or silver nitrate (AGNO3) mix

addition of coloured salts (e.g. copper sulphate CuSO4)

Collectors

Collectors may include:

litharge or lead (II) oxide (PbO) for pot fusion

silver (AGNO3) for the cupellation

Criteria for an 'acceptable' button

Criteria for an 'acceptable' button could include:

one piece, mass >20 g and <50 g

malleable

separates cleanly from slag

free of undecomposed ore, matte and speiss

Other precious metals

Other precious metals may include:

high gold, Platinum and Palladium

Separation of collectors

Separation of collectors may include:

cupellation

digestion

parting, annealing and weighing for a gravimetric finish

Contamination and losses

Contamination and losses 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

Records

Records may include:

pour sheets - date, time, client, pour number and preparation method

number of pots, positions of sample, blank and check in rack

visual appearance of samples, buttons and prills

corrective actions for specific samples

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, lower charge weight to compensate for high oxides, silicates and chromites

sulphides - adjust fusion time, 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, 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


Sectors

Unit sector

Testing


Employability Skills

This unit contains employability skills.


Licensing Information

Not applicable.