Job Title: Senior Mechanical Estimator (Mining)

Company: Loenbro, LLC
Business Unit/Department:   Estimating                                                     
Location: Gilbert, Arizona
Reports to:  Pre-Construction Manager
Employment Type: Full-Time
FLSA Classification: Exempt

About Loenbro

Loenbro is a trusted, long-term construction lifecycle partner to thousands of customers across the U.S. Our market spans all industries and our service offerings include Critical Electrical, Mechanical & Structural, Soft Crafts, Inspection, Underground Maintenance and Installation, and Fabrication. Our expertise lies in simplifying the complex and establishing long-standing relationships with our partners. We have a national presence but a local approach—every customer benefits from our capabilities and our care.

At Loenbro, we don’t just offer jobs—we build careers grounded in integrity, teamwork, excellence, and purpose. Join a team where your expertise is valued, your growth is supported, and your work helps maintain and enhance the critical infrastructure that powers communities across the nation.

Job Summary
The Senior Mechanical Estimator (Mining) is responsible for developing accurate, competitive, and comprehensive cost estimates for multi-discipline construction and industrial services projects supporting mining and heavy industrial clients. This role requires the ability to estimate across multiple service lines — Structural Fabrication & Erection, Piping, Mechanical Equipment Setting, Civil Earthwork & Concrete, and (as a plus) Electrical — and to synthesize those disciplines into cohesive, winning proposals. 

The ideal candidate combines strong technical and craft knowledge with commercial acumen, is comfortable reading complex drawings and specifications across trades, and can build relationships with clients, engineers, and subcontractors throughout the pursuit and proposal process. Works with Precon SME Estimators to collaborate an all inclusive bid when needing assistance.  

KEY RESPONSIBILITIES 

Estimating & Takeoffs 

• Prepare detailed quantity takeoffs and cost estimates for structural steel fabrication and erection, process and utility piping, mechanical equipment setting and rigging, civil earthwork, concrete (foundations, slabs, structures), and electrical scopes when applicable. 

• Analyze RFPs, RFIs, drawings, specifications, and scopes of work to identify all cost-driving elements and potential risks. 

• Develop labor hour estimates using historical production rates, craft labor agreements, and established estimating databases. 

• Solicit, evaluate, and level subcontractor and vendor quotes for scopes outside self-perform capability. 

• Build and maintain HeavyBid estimate templates, unit cost databases, activity and cost coding structures, and historical production data across all service lines. 

• Structure estimates so labor hours, crew makeup, quantities, and production rates can be cleanly exported and handed off to the Scheduling Department for CPM schedule development. 

Proposal Development 

• Compile complete, well-organized bid packages including cost narratives, schedules, exclusions and clarifications, and commercial terms. 

• Coordinate with Operations, Project Executives, and Safety to validate assumptions, means and methods, and constructability. 

• Support development of project execution plans, staffing plans, and schedule logic (5x10, 5x12, or other workweek models) as needed for client evaluation. 

• Partner with the Scheduling Department to deliver estimate-driven inputs for Microsoft Project schedules, and validate that the resulting schedule aligns with estimated durations, manpower loading, and equipment utilization. 

• Participate in bid strategy sessions and pricing reviews with leadership. 

Client & Site Engagement 

• Attend site walks, pre-bid meetings, and client interviews to gather scope clarity and build relationships. 

• Respond to client RFIs during the bid period with technical and commercial input. 

• Support post-award transition, providing estimate handoff and scope clarification to the project ops team. 

Cross-Functional Collaboration 

• Work closely with the Sales and Business Development team to align pursuits with pipeline strategy and account priorities. 

• Coordinate with Engineering (internal or client-side) on redlines, design clarifications, and constructability feedback. 

• Track win/loss outcomes and incorporate lessons learned into future estimates. 

REQUIRED QUALIFICATIONS 

• 5+ years of estimating experience in industrial or mining construction, with demonstrated exposure to at least two of the core service lines (Structural, Piping, Mechanical Equipment Setting, Civil/Concrete). 

• Strong ability to read and interpret civil, structural, mechanical, and piping drawings and specifications. 

• Proficiency with HCSS HeavyBid estimating software, or demonstrated ability to transition quickly from a comparable platform, along with advanced Microsoft Excel skills. 

• Proficiency with Microsoft Project, or the ability to structure and export estimate data — activity coding, labor hours, crew composition, quantities, and durations — in a format the Scheduling Department can use to build an accurate CPM schedule. 

• Working knowledge of MSHA regulations and mining site safety requirements. 

• Strong written and verbal communication skills, with the ability to present estimates clearly to internal and client stakeholders. 

• Valid driver's license and ability to travel to mine sites and client facilities as needed. 

PREFERRED QUALIFICATIONS 

• Experience estimating electrical scopes (substations, MCCs, underground and mine electrical distribution) is a strong plus. 

• Background as a craft tradesperson, foreman, or field supervisor in one or more of the core disciplines. 

• Advanced HeavyBid capability: custom biditem libraries, resource setup, activity coding, and HeavyBid-to-scheduling data exports. 

• Experience with self-perform contractors serving copper, gold, or other hard-rock mining operations. 

• Degree in Construction Management, Engineering, or a related field, or equivalent field experience. 

CORE COMPETENCIES 

• Multi-discipline fluency — comfortable moving between civil, structural, mechanical, piping, and electrical scopes on the same project. 

• Analytical rigor — builds estimates from the ground up rather than relying solely on historical rules of thumb. 

• Commercial awareness — understands margin, risk, and competitive positioning, not just cost. 

• Collaboration — works effectively across Sales, Operations, Engineering, and Safety. 

• Deadline-driven execution — manages multiple concurrent bids under tight timelines without sacrificing accuracy. 

PHYSICAL & WORK ENVIRONMENT REQUIREMENTS 

• Ability to travel to active mine sites, including underground and surface operations, for site walks and client meetings. 

• Ability to wear required PPE and pass site-specific safety orientations (MSHA Part 46/48 as applicable). 

• Primarily office-based with periodic field travel, estimated at 10–25%