Heavy Duty Apron Slab Design

Project Name

Peak Downs Industrial Area Upgrade – Apron Slabs

Client

BHP Billiton Mitsubishi Alliance (BMA)

Location

Peak Downs Mine

During recent upgrades to the BMA Peak Downs Mine Industrial Area, FIELD Engineers conducted feasibility analysis, budgeting and engineering design of heavy duty apron slabs that were installed between the heavy vehicle workshops.  The slabs were required to provide all weather access between the heavy vehicle workshops, improve stormwater drainage, and provide a barrier between the high voltage underground power running between the workshops, and the heavy-vehicle traffic on the surface.

The design needed to accommodate the traffic of mining machinery, including 400Tonne Excavators running on steel tracks.  Services and stormwater drainage had to tie into neighbouring systems.  The design and slab jointing had to allow for construction while activities in workshops continued, which required detailed traffic planning for industrial area.

Two aprons were designed, 5100 m2 and 2500 m2 in area respectively.  The sixty-four slabs were designed as 450 mm thick reinforced concrete panels with nominal dimensions  13 m x 9 m .

Load transfer at joints between slabs was designed using square dowels in elongated dowel boxes.  The poor quality subgrade material in conjunction with the high loads required the pavement design to be 600 mm thick to adequately support the slabs and to transfer concentrated loads to the subgrade.

To protect the slab from wear, the design replaced the costly wear-rails that are typically used in heavy duty slabs of this nature with a Fibrecrete dosage of 75kg/m3.  This reduced cost considerably, while allowing for a faster installation by removing the rail set-up process.

FIELD provided in-progress QA inspections during the construction phase to provide BMA peace of mind that the slabs were constructed to spec’. The end result has been a greatly improved industrial area for the Peak Downs Mine.