Sr./Staff Process Engineer - Detailed Engineering and Plant Design

Mariana Minerals•Houston, TX

About The Position

Mariana Minerals is hiring a Senior / Staff Process Engineer to execute detailed engineering deliverables for industrial process facilities. The role produces and owns the technical content and revision history of process deliverables—including P&IDs, line, instrument, and valve lists, control narratives, hydraulic models, equipment and bulk specifications, and procurement packages—and carries them through procurement, construction, and commissioning. The engineer owns the process design basis for assigned areas, develops process documentation and models, specifies equipment, and coordinates process requirements across engineering disciplines. The role also supports process safety reviews and construction and commissioning activities. Mariana Minerals describes itself as a software-first, vertically integrated minerals company focused on supplying critical minerals for energy, AI, and defense technologies.

Requirements

At least 8 years of process engineering experience delivering detailed design for industrial process facilities in an EPC/EPCM, owner’s engineer, or in-house capital projects environment.
Experience completing a detailed-engineering cycle on at least one greenfield or major brownfield project.
Bachelor of Science degree in Chemical, Metallurgical, or Process Engineering.

Nice To Haves

Professional Engineer (PE) license.
Lithium experience, including direct lithium extraction, spodumene leaching, crystallization, and battery-grade product specifications.
Copper experience, including heap and tank leaching, solvent extraction and electrowinning, tankhouse, and electrolyte circuits.
Slurry and solids handling experience, including thickeners, filters, pulp and tailings piping, and settling and erosion design.
Experience with data-centric P&ID platforms such as SmartPlant P&ID, AVEVA P&ID, or Plant 3D P&ID.

Responsibilities

Own the process design basis for assigned areas, including design cases and margins, turndown, utility and reagent demands, and the underlying first-principles assumptions.
Develop PFDs, heat and material balances, and P&IDs, and manage associated metadata in smart drafting and modeling software such as Plant 3D.
Develop P&IDs from concept through IFC, including equipment, instrumentation and control loops, isolation and relief philosophy, drains and vents, sample and utility stations, sloping and tracing notes, and tie-ins.
Manage and develop automated workflows for process data behind line, instrument, and valve lists, including line numbers and sizes, service conditions, design and test pressures and temperatures, pipe class selection, insulation and heat tracing, and instrument process data.
Build and maintain hydraulic models covering line sizing and pressure drop, pump and blower curves and duty points, NPSH margin, control valve and orifice sizing, slurry and two-phase lines, and gravity, launder, and vent flow.
Evaluate automation opportunities linking hydraulic models to heat and material balances and Plant 3D Data Manager.
Size and specify process equipment, including pumps, control valves, relief devices, heat exchangers, tanks and agitators, filters, thickeners, mixer-settlers, crystallizers, and solid–liquid separation equipment.
Write control narratives and functional descriptions with support from the controls engineering team.
Represent process engineering in PHAs and HAZOPs.
Coordinate detailed engineering across disciplines, including equipment lists and loads for mechanical, motor and instrument lists for electrical and controls, and layout, access, and maintenance clearances with piping and civil-structural teams.
Support construction and commissioning through RFI and field change resolution, P&ID walkdowns and field verification, loop checks and functional testing, water and first-feed startup, and as-built closeout.