Mobile Heavy Diesel Mechanics at Castle Hill.

Service Requirements at Castle Hill

Diesel fleet reliability is the mechanical backbone of open pit surface mining, and at Castle Hill the demand on heavy diesel assets is compounded by the Goldfields-Esperance semi-arid environment and a logistics chain anchored 43 km from Kalgoorlie. Evolution Mining Ltd. (100% owner) / NRW Holdings Limited (surface mining contractor) operates the site under a shared Mungari Operations logistics network, meaning diesel mechanic contractors must integrate with multi-tenement fleet management protocols rather than a standalone site arrangement. The open pit extraction method at Castle Hill places continuous mechanical load on large-format earthmoving equipment — hydraulic excavators, articulated haul trucks, dozers, and graders — all of which require field-capable heavy diesel servicing with OEM-aligned diagnostic tooling. Given the site's unconfirmed current activity level, RFQ scope must be written to remain executable across varying fleet utilisation intensities, from reduced-cycle maintenance schedules through to full production-support rotations. Scope documentation should specify minimum diagnostic equipment compatibility with Tier 4 Final and Stage V emissions-compliant engines as a minimum performance threshold.

• Ambient temperature capability: Demonstrated service delivery in sustained ambient temperatures of 40°C, with documented procedures for peak thermal events to 44°C — evidenced by minimum 24 months of Goldfields or equivalent semi-arid WA mine site exposure within the last five years.
• Fleet class coverage: Verified OEM-authorised or OEM-trained capability across at least two of the following platforms common to open pit surface fleets: Caterpillar 785/793 series haul trucks, Komatsu PC1250/PC2000 excavators, or equivalent 100-tonne-plus class equipment — evidenced by OEM service records or authorisation letters submitted with tender response.
• Field diagnostic tooling: Contractor must deploy field service vehicles equipped with onboard diagnostic software (e.g. Cat ET, Komatsu KOMTRAX/VHMS, or equivalent OEM-specific tools) capable of fault interrogation without workshop repatriation — minimum one fully equipped field unit per four-person crew deployed.

Site-Specific Operational Constraints

Conditions procurement must communicate to all bidders in tender documentation for Castle Hill.

• Environment: Goldfields-Esperance semi-arid conditions impose sustained summer ambient temperatures of 40°C and peak events to 44°C, combined with fine laterite dust ingestion risk that accelerates air filter and fuel system degradation. Tender documentation must require contractors to address heat-stress management protocols for field personnel and thermal protection procedures for diagnostic electronics and lubricants carried in field service vehicles.
• Logistics: Castle Hill sits approximately 512 km from Perth, with Kalgoorlie as the nearest service hub at ~43 km. Primary site access is via sealed and unsealed roads connecting to the Great Eastern Highway corridor. All parts, consumables, and tooling must be pre-positioned at a Kalgoorlie-based depot or equivalent consignment-stock arrangement — reliance on same-day Perth freight is not an acceptable supply continuity model and must be excluded from contractor logistics plans.
• Response SLA: Emergency breakdown call-out response must be achievable within 2–4 hours from Kalgoorlie hub to site. Extended mobilisation for non-critical scheduled maintenance must be achievable within 12–24 hours. Contractors must document their Kalgoorlie or equivalent regional staging capability as a mandatory RFQ attachment.
• Roster: DIDO roster compatibility from Kalgoorlie base hub is required, consistent with the Mungari Operations logistics model. Contractors must specify their proposed shift pattern (minimum 10-hour days) and confirm standby crew availability for unplanned breakdown coverage outside standard roster windows.
• Camp/facilities: Site-provided accommodation status is unconfirmed given the site's current activity level. Contractors must declare self-sufficiency capability — including portable ablutions, catering, and crew transport — as a contingency within their tender submission. Any reliance on site-provided facilities must be explicitly scoped and confirmed with Evolution Mining Ltd. (100% owner) / NRW Holdings Limited (surface mining contractor) prior to RFQ close.

Contractor Capability Checklist

Minimum evaluation criteria for shortlisting Mobile Heavy Diesel Mechanics contractors at Castle Hill. Each criterion must be verifiable via documentation submitted with tender response.

• Technical certifications: OEM authorisation or OEM-recognised training certification for at least two heavy equipment platforms relevant to open pit surface fleets (Caterpillar, Komatsu, Hitachi, or Liebherr); compliance with AS 4024 series (plant and machinery safety) where applicable to field service operations.
• Personnel tickets: All field mechanics must hold a current Certificate III in Mobile Plant Technology (MEM30219 or equivalent) or higher; WA Construction Induction Card (White Card) mandatory for all personnel; site-specific surface mining competencies to be confirmed against NRW Holdings Limited site safety management system requirements prior to mobilisation.
• Mobilisation SLA: Documented evidence of 2–4 hour emergency response achievement from a Kalgoorlie or equivalent Goldfields-Esperance regional staging point — supported by at least two reference contacts from comparable remote WA mine site engagements within the last three years.
• Public Liability insurance: Minimum AUD $20M per occurrence (Certificate of Currency required with tender response).
• Professional Indemnity: Minimum AUD $10M aggregate — required where contractor scope includes technical specification of repair methods, component substitution recommendations, or maintenance programme design advice.
• Workers Compensation: Full statutory cover under WA law (WorkCover WA — Injury Management Plan required and must be submitted as a tender attachment).
• Site exposure: Minimum three years of documented heavy diesel field servicing at open pit surface mining operations in WA, with at least one reference site involving gold or base metals extraction in a remote Goldfields or Pilbara environment — commodity type and extraction method to be specified in the capability statement.
• Safety systems: HSE management system certified to ISO 45001:2018 or equivalent; ICAM (Incident Cause Analysis Method) trained personnel required at supervisor level; pre-mobilisation safety documentation package must be submitted and accepted before any site access is granted.

Regulatory & HSE Framework

All mobile heavy diesel mechanic activities at Castle Hill are governed by the Work Health and Safety Act 2020 (WA) and the Work Health and Safety (Mines) Regulations 2022 (WA), administered by WorkSafe WA. For field diesel servicing in an open pit surface environment, specific attention is required under the WHS (Mines) Regulations 2022 provisions relating to plant management, hazardous substances handling (lubricants, fuels, DEF/AdBlue), and isolation and lockout/tagout (LOTO) procedures for heavy mobile equipment. The Evolution Mining Group HSE Framework applies at the tenement level, with the NRW Holdings Limited site-level safety management system governing day-to-day surface operations at Castle Hill — contractors must obtain and review both documents prior to scope finalisation. Supplier prequalification is managed through the Avetta platform in conjunction with the Evolution Mining Supplier Portal (URL not publicly confirmed through available sources at time of writing — procurement teams must obtain the current registration link directly from the operator's procurement contact). Portal registration is mandatory prior to RFQ participation. All contractors must complete site-specific induction via Evolution Mining Ltd. (100% owner) / NRW Holdings Limited (surface mining contractor) procedures before mobilisation, with induction records retained on file for the duration of the engagement.

Sourcing Qualified Contractors

No confirmed tender activity for Mobile Heavy Diesel Mechanics at Castle Hill was identified in available procurement intelligence at the time this briefing was prepared. The regional labour pool for this service in Goldfields-Esperance is centred on Kalgoorlie (~43 km from site), with approximately five active providers identified in the region capable of delivering field-based heavy diesel mechanics to remote open pit operations. This is a constrained market relative to the Pilbara, and the 512 km Perth-to-site distance effectively eliminates Perth-based contractors without a demonstrated Kalgoorlie staging presence from realistic consideration. No incumbent contractors were confirmed through available research; procurement must conduct independent market engagement to establish current provider availability and capacity. Given the semi-arid operating environment and the OEM tooling and certification requirements specified above, allow a minimum of six to eight weeks for prequalification, portal onboarding, and capability assessment before target RFQ close. Early market engagement — including a Request for Information to the ~five regional providers — is recommended to validate depot capacity and roster availability before formal tender release.