pitt&sherry have a long history providing specialist services to the mining and minerals processing industry.

Our range of services and a capability have grown significantly over the past decade so that we can now offer a range of specialist services to developing or existing mine sites and mineral processing facilities. The pitt&sherry team has significant mine backfill expertise with the investigation of backfill materials, and the design and operation of backfill plants. Designing, constructing and operating a backfill system that reliably meets performance requirements is critical to the safety and financial success of an underground operation.

To perform adequately, a mine backfill must have the following properties:

• Adequate strength to withstand expected internal stresses upon exposure of the fill
• Minimal degree of segregation of binder and bulking material within the fill upon placement
• Free draining of excess water or chemical absorption of excess water in placed fill
• Curing time to reach the desired strength, which is acceptable within the production schedule
• Flowability to be delivered to the stopes in a pipe, conveyor borehole reticulation system or by trucking and to distribute evenly across the area of the stope
• Chemical stability with respect to long term retention of strength.

Backfill binders are often one of the most expensive mining consumables. It is important that binder contents and mix designs are optimised to achieve the target fill strength at the lowest cost. pitt&sherry personnel have experience with the investigation of various backfill binders including cements, pozolans (flyash, ground slags, ground glass) and gypsum. We have developed and supervised test programs to investigation backfill mix designs and binder combinations. Our team has also undertaken testing of cured backfill to assess the placed fill is achieving the design intent.

pitt&sherry structural and geotechnical engineers are familiar with backfill barricade design and drainage systems. Our process engineers have operated backfill plants and undertaken commissioning and plant optimisation studies.

pitt&sherry apply their backfill materials, plant design and operating system knowledge in the following areas:

• Scoping, pre-feasibility, feasibility, design and costing studies.
• Backfill system optimisation
• Material characterisation and mix design optimisation
• Operational systems design including safety procedure, barricade design and fill sequencing
• Operational systems audits, trouble shooting and on-site backfill technical support
• Geotechnical backfill performance modelling including local and regional stability analysis, and numerical modelling.