The greatest unknowns in any shaft excavation program, and those which are likely to have the most dramatic effect on performance and cost, are the geotechnical and hydrological conditions in the region of the shaft.

pitt&sherry have a long history of providing specialist geotechnical services. Our range of services and capability has grown significantly over the past decade so that we can now offer a full range of shaft site investigation, geotechnical evaluation and shaft lining design services. Our shaft team have assessed shafts from 0.9m to 12m in diameter, with depths up to 1400m.  

pitt&sherry tailor shaft engineering evaluations to suit client requirements, from scoping studies through to detailed design and construction documentation.

Shaft planning services

pitt&sherry can provide a full range of up front work for shaft development projects including development planning, site investigations and geotechnical assessment.

pitt&sherry’s capability in this area includes:

• Mine scale shaft location assessments
  • Topographic mapping and survey
  • Interpretation of aerial photographs
  • Geotechnical mapping
  • Geophysical studies
• Regional & mine scale structural geology modelling
• Regional hydrogeological assessments
• Mine scale numerical modelling; stress & subsidence assessments
• Preliminary excavation method & support assessments
• Project risk assessments

Shaft site investigations

pitt&sherry can provide a full range of shaft site investigation field services from engagement of drilling contractors, drilling supervision, core logging, boxing and sample selection, geophysical investigations, and packer testing.

Our team has undertaken shaft investigations for:

• Hoisting shafts
• Ventilation shafts
• Ore passes
• Coal bins
• TBM access shafts
• Pump station shafts
• Shafts in hard rock, soft rock and soils
• Coal mine shafts
• Metalliferous mine shafts

Geotechnical assessment

pitt&sherry utilise multiple empirical and analytical methods to undertake geotechnical assessments for shaft projects.

Our approach includes:

• Structural geology modelling
• Rockmass classification techniques
• Kinematic wedge analysis
• Stress analysis
• Convergence / confinement analysis
• Assessment of seismicity

Method selection & design

The interpretation of the geotechnical and hydrogeological assessments yields information for shaft excavation method selection and support including:

• Shaft collar & presink design
• Headframe foundation design
• Raise bore or blind borer foundations
• Short term and long term wall stability
• Face stability for raise boring methods
• Drillability, cutter wear and penetration rate assessments
• Ground improvement techniques
• Assessment of squeezing
• Water management
  • Grouting
  • Water rings
  • Dewatering bores
  • Face pumping
• Temporary & permanent support systems
• Liner design & specifications
• Shaft excavation risk assessment

Construction phase services

pitt&sherry’s shaft engineering team have worked for both mine owners and shaft excavation contractors. Our on-ground experience in the excavation phase of shaft projects has enabled us to refine our shaft assessment and design process.

Our construction phase services include:

• Project management
• Risk assessments and development of Safe Work Method Statements
• Certification of structures and plant
• Contract administration
• Geotechical mapping & documentation
• Design verification
• QA monitoring and testing

Industry collaboration

pitt&sherry aim to adopt a “best for project approach” and regularly work in collaborative teams with specialists to complement our in-house skills. This collaboration enables us to provide a full-service capability across the mining project lifecycle, from concept to closure. pitt&sherry personnel have provided engineering advice on shaft projects throughout Australia, Indonesia, Brazil, South Africa, Singapore, Hong Kong, Philippines, PNG, Mongolia and New Zealand.