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. pitt&sherry’s shaft specialists have undertaken assessments for over 35km of shafts from 0.9m to 12m 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 assessmentsTopographic mapping and surveyInterpretation of aerial photographsGeotechnical mappingGeophysical studiesRegional & mine scale structural geology modellingRegional hydrogeological assessmentsMine scale numerical modelling; stress & subsidence assessmentsPreliminary excavation method & support assessmentsProject risk assessmentsShaft 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 shaftsVentilation shaftsOre passesCoal binsTBM access shaftsPump station shaftsShafts in hard rock, soft rock and soilsCoal mine shaftsMetalliferous mine shaftsGeotechnical assessment pitt&sherry utilise multiple empirical and analytical methods to undertake geotechnical assessments for shaft projects.Our approach includes:Structural geology modellingRockmass classification techniquesKinematic wedge analysisStress analysisConvergence / confinement analysisAssessment of seismicityMethod selection & designThe interpretation of the geotechnical and hydrogeological assessments yields information for shaft excavation method selection and support including:Shaft collar & presink designHeadframe foundation designRaise bore or blind borer foundationsShort term and long term wall stabilityFace stability for raise boring methodsDrillability, cutter wear and penetration rate assessmentsGround improvement techniquesAssessment of squeezingWater managementGroutingWater ringsDewatering boresFace pumpingTemporary & permanent support systemsLiner design & specificationsShaft excavation risk assessmentConstruction phase servicespitt&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 managementRisk assessments and development of Safe Work Method StatementsCertification of structures and plantContract administrationGeotechical mapping & documentationDesign verificationQA monitoring and testingIndustry collaboration pitt&sherry adopt a “best for project approach” and regularly work in collaborative teams with industry leading 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.