Geochemistry

What we do

We deliver end to end geochemistry for mining, energy, and infrastructure, covering baseline characterisation, operational support, risk assessment, remediation, and closure. Our work spans soils, waste rock, tailings, sediments, process water, groundwater, and surface water.

Where we add value

  • Exploration & Planning: Baselines, material characterisation, and siting decisions
  • Operations: Process/water quality control, waste management, risk mitigation
  • Closure & Rehabilitation: Long term performance prediction and verification
  • Compliance Support: Monitoring programs and defensible, decision grade reporting

What we test and analyze

  • Matrices: Soil/rock, waste rock, tailings, sediments, porewater, groundwater, surface water, process water
  • Chemistry: pH, alkalinity/acidity, major ions, sulfate, nutrients, DOC/TOC, dissolved/total metals, organics
  • Mineralogy: XRD, SEM EDS, QEMSCAN for sulfides, carbonates, oxides, secondary salts
  • Specialty: Redox speciation, metal mobility, leachability, acid/neutralisation capacity

Acid Rock Drainage (ARD/AMD) Characterization 

Comprehensive programs that predict risk, quantify loads, and design practical controls:

Static Prediction (Screening)
  • Acid Base Accounting (ABA): AP, NP, NNP, NP/AP; total S with sulfate/sulfide partitioning
  • Carbonate/Neutraliser Assessment: Modified Sobek, fizz tests, carbonate quantification
  • Mineralogical Controls: XRD/SEM EDS/QEMSCAN to identify reactive sulfides, neutralisers, and secondary salts
  • Indicative Leaching: Short term water leaches (e.g., SPLP/site specific) for metal mobility signals
Kinetic Testing (Rates & Lag Time)
  • Humidity Cell Tests (HCT, ASTM D5744): Weekly effluents for pH, sulfate, alkalinity/acidity, Fe/Al/Mn/metals; acid generation rates & time to onset
  • Columns/Barrels: Site specific hydrology and oxygen ingress; validate blending/cover concepts
  • Field Test Pads: Instrumented pilot plots to de risk scale up and calibrate models
Hydrogeochemical Modelling
  • Speciation & Saturation: PHREEQC/Geochemist’s Workbench for complexation and mineral controls
  • Reactive Transport: Predict acidity/metal migration and treatment performance under realistic flow paths
  • Mass Balance: Net acidity and metal load calculations for receptors and treatment sizing
Monitoring & Verification
  • Network Design: Groundwater/surface water points, lysimeters/porewater in waste/tailings
  • Parameters & Frequency: Field (pH/EC/DO/ORP), full chemistry suites, trend analysis, control charts
  • Performance Metrics: Acid/alkalinity balance, sulfate trends, Fe/Al/Mn loads, secondary mineral formation
Mitigation & Management
  • Source Control: PAG/NAG segregation, selective mining, blending strategies
  • Covers & Barriers: Store and release (ET), oxygen barrier/low k layers, capillary breaks, geomembranes
  • Alkalinity Addition: Lime/limestone dosing, anoxic limestone drains (ALDs), successive alkalinity producing systems (SAPS)
  • Treatment Trains: HDS neutralisation, aeration/oxidation, co precipitation, polishing filters
  • Passive Systems: Constructed wetlands, bioreactors, permeable reactive barriers
  • Closure Planning: Performance criteria, monitoring triggers, adaptive management

Typical Deliverables

  • Sampling & Analysis Plans (with QA/QC program)
  • Static/Kinetic ARD/AMD test reports (ABA, HCT, columns) with interpretive narratives
  • Hydrogeochemical models and load/flux calculations
  • ARD/AMD Risk Register and Mitigation/Management Plan
  • Monitoring program design with KPIs and dashboards
  • Closure geochemistry criteria and verification plans