BHT LME04 Diversion Road Construction

The Challenge

• Operational environment: Works delivered beside an active Mine Access Road with constant mining traffic, requiring strict RTIO controls and continuous coordination for safe staging.
• Tie-in complexity: Both ends required full-depth reconstruction under traffic, supported by 500m temporary diversions to maintain uninterrupted vehicle flow.
• Drainage constraints: Flood-prone terrain demanded early culvert installation, including five 900mm MAR culverts and an additional off-formation culvert tied to future HME works.
• Borrow pit control: Select fill and basecourse had to be sourced, tested, and hauled from approved borrow pits while maintaining production sequencing and Borrow Pit Management Plan compliance.
• Program pressure: LME04 sat directly on the critical path for tunnel works and MAR reopening, leaving no float and requiring precise staging and rapid approvals.
• Documentation burden: Full traceability was required for lots, tests, drainage installs, survey as-cons, and sealing records to satisfy RTIO verification requirements.

MESCo’s Role

MESCo provided a Site Project Engineer and a dedicated HSE Advisor to support delivery, drive compliance and maintain integrated systems across the full LME04 scope.

Engineering Support: Our engineer was embedded with the construction team to lead QA/QC implementation, coordinate staging and keep daily sequencing aligned with program milestones.

HSE Support: MESCo’s on-site HSE Advisor provided full safety oversight, daily field leadership, risk management, and alignment with RTIO HSE standards throughout all works and traffic transitions.

Key responsibilities included:

• Implementing earthworks QA/QC framework aligned to HD1S Technical Specification
• Developing and managing lot registers, test plans, and survey verification flows
• Coordinating tie-in staging, traffic switches, and temporary works sequencing
• Oversight of drainage installation, culverts, and trench bedding compaction
• Daily reporting to EPCM/RTIO, including progress, testing, HSE and compliance
• Field-level HSE leadership including inspections, risk controls, PTWs, JHAs and behavioural safety engagement
• Providing rapid NCR/TQ support to keep decisions moving and prevent bottlenecks

Key Deliverables

• Project-specific construction management plans
• QA/QC framework for earthworks, pavement, culverts and sealing
• Survey verification for foundations, layers and final geometry
• Drainage installation and culvert bedding documentation
• Borrow pit material testing and compliance records
• Traffic staging plans for both tie-ins and temporary diversions
• Daily QA/QC and HSE reporting and field inspections
• Site risk assessments, PTWs, JHAs and safety observation records
• Bituminous seal design and verification package
• NCR logging, HSE action tracking and closure management
• Full close-out pack including lots, test reports, ITPs, HSE documentation and as-constructed survey

Outcome

• All tie-ins completed safely under traffic with zero operational disruption.
• All compaction, foundation and basecourse tests passed on first submission.
• Seal works approved with no corrective actions required.
• Drainage installations verified with complete as-cons and bedding records.
• No NCRs escalated; all minor items were closed before submission.
• Final QA/QC close-out pack accepted without revisions.
• Project delivered in line with the 3-month target despite weather and traffic interface constraints.
• Strong HSE performance with proactive field control and no significant incidents.

Lessons Learned

• Early traffic and staging planning allowed tie-ins to be delivered safely with minimal impact to live MAR operations.
• Embedding borrow pit testing into daily QA workflows improved material consistency and reduced rework.
• Real-time coordination between survey, QA and HSE accelerated approvals and improved field control.
• Front-loading drainage installation protected works from flooding and safeguarded the schedule.
• Clear interface management with RTIO operations ensured quick decisions and avoided delays.
• MESCo’s integrated engineering and HSE support strengthened compliance, lifted field performance and delivered a clean, defensible close-out package.