A Protocol and Standard for Mine Ventilation Studies

1. A Protocol and Standard forMine Ventilation Studies Rick Brake Mine Ventilation Australia

2. Populations: USA: 304 million Aust: 22 million

3. Why do we ‘need’ a generally-accepted protocol and standard? • Major mining houses are developing internal stds • World bank & others developing own stds • Legal implications of duty of care—an industry accepted standard helps demonstrate ‘care’ • Building codes and national or international stds • Prosecution policies of regulators • Part of “quality assurance” principles • Example: internationalisation of “ore reserves” codes • Increasing use of peer review • Will benefit stakeholders

4. Safety and Health “Ventilation planning for the Westray mine did not address the requirements for a comprehensive system of fresh-air circulation and methane removal. The plan on which the ventilation was based was merely a brief outline in a feasibility study. A comprehensive engineering study by competent ventilation experts was not completed and documented before approvals were requested…” The Westray Story-A Predictable Path to Disaster, Report of the Westray Mine Public Enquiry into the death of 26 miners on 9 May 1992: Province of Nova Scotia, Justice K P Richard, Commissioner

5. Peer Review • “... an assessment of an opinion or study conducted by a person or persons of similar expertise to the author” • Typically involves an additional cost of 2 to 5% of the study cost • Peer review has stood the test of time with regard to technical publications; logical to extend it to study processes

6. Peer Review (2) • Two types now in use in Australia: • Internal peer review within a consulting firm • Independent peer review organised by client • By a third party • Specialist panel within the client’s organisation • For effective peer review, reviewers need: • To be technical competent (i.e. “peers”) • Have no stake in the outcome of the review (unbiassed) • Must be formal, rigorous and carefully documented else can become unfair and “witch hunt”

7. Hold and Review • In a major study, there are many technical teams • Battery limits separate the teams • A key issue is to ensure disparate technical teams aren’t operating under conflicting design criteria or assumptions • Example: rock mechanic team has resolved that maximum unsupported vertical airway size can only be 3.5 m, but ventilation team is assuming 4.5 m is acceptable • Intention is to avoid rework, and additional costs and delays that go with it

8. Hold and Review (2) • Hold & Review mtgs are formal mtgs at which key representatives from each technical discipline listen to each other’s presentations on the status of their design • Purpose: • What incompatibilities exist in the designs? • What duplication exists? • What has “fallen between the cracks” (no-one is addressing)? • What new opportunities for improvement exist in the design?

9. E-rooms • Studies often produce hundreds of interim file notes from large number of individuals & teams • Many have to be circulated for review • Significant issue is documents being: lost, misfiled, or delayed to the point of adverse effect • E-rooms: • Allow documents to be shared for review simultaneously • Provide for formal document control ensuring those required to provide feedback do so • Allow documents too large for email to be shared

10. Implications of Duty of Care • Upside is that: • Provides “freedom from prescription” so that innovation is possible with flexible solutions • Captures risks not noted in regulations incl new risks • Encourages greater ownership of risk m’ment by industry • Downside is that standards may become worse • Duty of Care is often linked to the “as low as reasonably achievable” (ALARA) i.e. ALARA defines the standard of the “duty of care” • Meeting minimum statutory requirements is not sufficient • How can “duty of care” be established, and demonstrated / audited?

11. Duty of Care: Client’s perspective • Clients need to establish industry “good practice”? • This changes over time, so major new studies need to re-establish what is ALARA? • Importance of bench-marking • Importance of risk assessment • Importance of internal standards for consistency • Importance of internal audit processes

12. Duty of Care: Consultant’s perspective • Many issues are similar to the Client’s perspective • Consultant’s developing own “internal standards” • Dilemma when client does not want to meet “duty of care” as consultant believes it to be • Either withdraw from engagement, or use risk assessment process (with client) to demonstrate duty of care and ALARA is still being met

13. Duty of Care: Regulator’s perspective (Compliance [Prosecution] Policy) (1) • Sufficiency of safety management plans • Implementation of safety management plans • Training of personnel in terms of: • Content of the plans • Accreditation to be competent in the plans • Understanding of implication of content of the plans

14. Duty of Care: Regulator’s perspective (Compliance [Prosecution] Policy) (2) • Communications in the organisation in terms of: • Internal comms within & between depts & individuals • External comms between company & other orgs • Retention of knowledge base (corporate memory) • Previous incidents of this type • Risk assessment process esp controls in place • Good practice across the industry • What other options were considered, if any • Audit systems in place

15. Implications for ventilation studies • Must include examination of industry good practice • Must demonstrate that alternative solutions were examined, and reasons for rejection (esp if lower risk) • Must be linked to risk assessment at some stage

16. Management of a Technical Study (3) • Irrespective of level of study, solution presented must be tangible, i.e. design presented can be implemented within existing knowledge, technology & experience • Opportunities for improvement are listed • Study is risk assessed before going to next phase of study

17. Management of a Technical Study (5) • In practice, it is difficult or impossible to deliver study on time, to the required standard, meeting the “fit for purpose” objectives and within budget • Consequences of study not meeting required standard, or not meeting “fit for purpose” could be very damaging • Study manager needs to have sufficient ‘clout’ to ensure these two key objectives are met, despite organisational push on the other two (time & cost)

18. Key issues for multi-disciplinary team: • Purpose/objectives, deliverables & level of confidence of study must be identified & agreed • Study needs experienced study manager • Battery limits for various sub-teams/disciplines must be set out and agreed • List of overall design specs must be owned by study manager and is a controlled document • Cost & time estimates must be realistic & good controls in place • Regular formal and informal communications • Formal Hold and Review meetings

19. Scope of a mine ventilation study • Review of ventilation hazards (gases, dusts, radon, heat, spon comb, etc) & management controls • Primary ventilation network at all key milestones in the mine life (volume & distribution of air) • Secondary/auxiliary ventilation design • Review of egress & entrapment provisions over life • Develop ventilation management plan covering day to day operation & management of the vent system including TARPs, SWPs and SOPs • Formal risk assessments for normal activities & abnormal activities (e.g. power failure, fire, etc)

20. Special problems of “brownfields” sites • Competition and conflict for limited plant & equipment (airflows, intakes/returns, etc) • Existing mine is essential for current production • “Future mine” is essential for longer-term prod • Inevitable human resource conflicts and personality issues between the management teams • Problems of adopting new “good practice” HR or safety or operating practices whilst leaving existing ones alone • Overall higher complexity of brownfields site with numerous interactions well into life of project

21. Required inputs for a ventilation study (1) • Dust, radon and/or methane or other airborne gaseous, fume or particulate contaminants or asphyxiants (e.g. nitrogen) • Gas contents of orebody/coal seam and adjacent strata; issues of gas drainage • Spontaneous combustion potential • Outburst potential • Water inundation (flooding) potential • Dust audits, silica (or other contaminant) contents of strata • Production, development, diamond drilling, raiseboring (or other vertical development) and production drilling schedules • Other important schedules or deadlines (e.g. construction schedules) • Mining methods, layouts, mine design, etc

22. Required inputs for a ventilation study (2) • Manpower schedule, by job type and location – for both production and construction phases • Major mobile equipment schedules, especially diesel equipment (maximum kW rating, dimensions, speed loaded and unloaded, up and down ramp, tonnes moved) • Mode of operation of diesel equipment (where travel, when, truck/loader combinations) • Diesel fuel usage, average and maximum per shift • Fixed electrical plant and efficiencies • Any special areas requiring filtered air or special ventilation (e.g. control rooms, cribrooms, offices, ventilation at crusher jaws, transfer points on belts, tipping points) • Coal, ore, mullock/waste or other materials handling flowcharts

23. Required inputs for a ventilation study (3) • Humidity limits for ore/waste including transfer points • Humidity limits for ground control/rock strata • Backfill system and operation, type of fill, method of placement • Locations of fuel and oil storage, refuelling, other major stores, combustible material, etc • Parking arrangements • Special fire fighting standards • Special egress or entrapment standards • Any maintenance arrangements impacting on egress (outages, inspections, etc) • Minimum medical/physical requirements for continuing employment or for visitors

24. Required inputs for a ventilation study (4) • Blasting arrangements: development and production, bins, chutes, etc, including frequency of blasting: development and production • Re-entry times after blasting etc • ANFO and other explosives consumption rates: development and production • Cement usages and consumption rates • Oxidation rates (to SO2 and/or CO2) • Working in heat protocols • Other special ventilation-related hazard protocols • Internal corporate ventilation/workplace environment standards for each job type (i.e. typical ventilation arrangements) • Statutory (legislative) requirements • Internal (company or mine) generic standards, hazard management plans, etc

25. Required inputs for a ventilation study (5) • Any noise criteria (impacting on noise insulation or siting of fans etc) • Any sources of dust, e.g. due to cutting, loading, etc • Dust controls (e.g. sprays) at drawpoints, tipples, conveyors, roads • Other sources of heat • Surface climate (WB, DB, BP) by hour for minimum of six years • Surface elevation above sea level • Depth of mining operations • Near-surface virgin rock temperature and geothermal gradient • Rock thermal conductivity, thermal capacity, diffusivity, density • Maximum heading lengths for auxiliary development, development heights and widths • Method of auxiliary ventilation, type and size of ducts, leakage factors • Any existing ventilation circuits, fans (including fan curves), controls etc

26. Required inputs for a ventilation study (6) • Any existing cooling devices • Usage and policy on air-conditioned cabins in mobile equipment and fixed plant • Mining (especially horizontal and vertical development) and ventilation (fan, controls, ducting) costs • Friction (“k”) factors and shock losses used or measured in the operation • Any surface considerations (dust from quarrying etc, prevailing winds, grass/bush fires, nearby plant) • Surface environmental limits on fans and shafts: noise, dust, water, smell, visual amenity • Shaft, raise and other major airway resistances and last time measured • Standards in regard to allowable pressures on ventilation doors (airlocks) or other ventilation controls

27. Required inputs for a ventilation study (7) • Ventilation or isolation of caved regions or goafs; leakage and pressure balancing • Network analysis and validation (comparing to measured data) • Multi-level tipping controls or protocols • Ground/fissure water in mine (amount, location, temperature (if very hot)) • Location of shafts, fresh and return air raises, distances apart (determines typical auxiliary ventilation line configurations and lengths) • Wetness of shafts. If wet, potential for water corrosion or erosion on fans. Potential for the shaft to be subject to erosion or sloughing or water plugging • Natural ventilation pressures; seasonal changes; impacts of refrigeration on natural ventilation pressures

28. Required inputs for a ventilation study (8) • Network simulation program used • Other computer programs in use or required to be used • Data on ventilation monitoring (e.g. strata gases, diesel exhausts, airflows, on-line monitoring) • Recent or relevant ventilation or feasibility studies • Any other safety aspects that need to be considered • Any recent ventilation audits completed • Any concerns from the operators or planners about current or future ventilation problems • Any telemetering, remote monitoring or remote operation/control requirements

29. Characteristics of phased approach to studies • An increase in knowledge and confidence • A reduction in risk to acceptable limits (risk is never eliminated completely) • Significant increases in expenditure on project evaluation (design, drilling, metallurgical testing, etc) for each stage • An increase in allocation of resources and personnel to the project and study • An increase in third party stakeholder involvement • Escalating internal momentum and expectations making major changes in direction or cancellation of the project increasingly difficult

30. Basic objective of phased approach to studies • Screening projects so that excessive monies are not spent on projects that could have been rejected at a lower level of study. • Ensuring that at a more detailed study stage, it is not possible to come up with credible options that should have been considered at an earlier phase, and which may then require a substantial amount of additional work to either adopt or eliminate • Remove bias and make more sound investment decisions

31. Required level of confidence for a ventilation study • Tendency in past to proceed very quickly to final feasibility study “saving time and money” • Meant alternative approaches not properly considered • Best possible outcome is sub-optimal design • Worst possible outcome is complete failure • Phased approach to studies gives lowest overall cost and fastest study time, in long run

32. Phases of study (1)

33. Phases of study (2)

34. Phases of study (3)

35. Phases of study (4)

36. Summary and conclusions • No national, international, or professional standards for mine ventilation studies at present • “Duty of Care” and ALARA will push our profession towards being able to demonstrate consistency and quality that will meet peer review • Some codification of the study process and deliverables is in our own interest, and that of our stakeholders (clients) as well as the Public • Any standard is likely to develop over time, and may never be fully formalised