Modular construction is by no means a recent development within the built environment. Many of the first European built structures in Australia were pre-fabricated and transported in flat pack for assembly here. The drivers causing the viability of this building solution are still present today as much as they were over 200 years ago. This is no more apparent than in the mining sector where huge workforces require up-to-code accommodation in remote, mineral-rich regions of the country. Writes Greg Quinn.
Camps versus Villages
Resourcing constraints caused by high accommodation and transport costs and a shortage of skilled labour in remote areas can make traditional building methods cost-prohibitive for the mining industry. For many years, the four-person cabin-style donga was, and in many cases still is, the mining camp accommodation staple. This style of accommodation is cheap and flexible, but represents a dramatic drop in living standards for workers coming from cities and suburbs. For mine management, this can lead to an increase in downtime, a drop in employee morale and difficulties recruiting and retaining skilled employees.
Increasingly we are seeing the emergence of single person accommodation units set in a village style layout. This style of accommodation is more appealing to employees however direct costs can typically be higher per bed. Some of these costs are offset by savings to operational costs, increased staff retention (avoiding repeat recruitment fees and additional training expenses), lower transport demands and downtime penalties.
BHP Billiton Mitsubishi Alliance has recently delivered multiple village style accommodation options in the Bowen Basin towns of Moranbah and Dysart which were delivered in prefabricated form. This included the central facility complete with roof top services decks and clerestory roof sections transported independently to meet transport restrictions.
Building up versus out: Programming Advantages
Where land values are high or encroaching mining leases restrict expansion, two storey pre-fabricated camps are becoming increasingly more common. More recently a third level is being added to further reduce the development and environmental footprint. A by-product of building up rather than out is the enhancement of the communal feel of the camp – bringing a little bit of the city to the country for FIFO workers.
Vertical stacking of prefabricated accommodation is becoming more cost effective through the development of detailing to manage the inherent challenges with this form of construction. The programming advantages over traditional in-situ build become magnified with each increase in vertical elevation. Significant reductions in on-site man hours are the biggest advantage to this type of construction. With labour-intensive finishing trades, such as tiling and painting already completed in each module, there is a dramatic reduction in the number of workers needing to access each floor. A reduction in the need for material hoists, less demand on the lunch room and ablutions block and reduced travel and accommodation expenses can see cost savings mount into the hundreds of thousands.
The inherent savings in modular methodology were demonstrated on a recent project Hutchinson Builders undertook to provide multi-level modular accommodation for the Australian National University and Central Queensland University. The construction cycle programme savings achieved were over 50% with a typical 12 month project being delivered in just five.
Benefit of Prefabrication
Prefabrication of the built form across all sectors can provide more than a 35% time reduction in project delivery. Hutchinson Builders recently completed two similar bath house projects in a real time experiment to settle the argument of prefabrication versus in-situ design. In the experiment, a pre-fabricated version of a mine-compliant bathhouse was completed three months earlier than the equivalent in-situ build. On-site man hours were also reduced by over 70%. The experiment also highlighted the additional safety benefits of eliminating high risk activities associated with working at heights.
The reduction in man-hours also means a reduction in the costs associated with transporting, accommodating and feeding construction workers in remote areas. The cost savings available here are both direct through the reduction of demand for these essentials but more significantly the indirect savings of a reduced construction camp size and the flow on into environmental benefits.
The future of prefabrication is broadening to include larger format structures making up MIA areas of mine sites such as bath houses, training rooms and administration offices. Though not new in the temporary ‘donga’ style, the challenge is to replicate the look, feel, longevity and high level finish of traditional in-situ buildings typically found in the CBD. This includes highset acoustic ceilings. As with the residential form there are productivity advantages in being able to re-create the work environment in remote locations. Tradesmen from traditional construction sites transfer their craftsmanship to these prefabricated buildings however higher engineering standards are required to accommodate the greater loads of transport and lifting the modules into place.
The modular or prefabricated construction sector is still maturing here in Australia compared to the developed markets of Europe and the US, however we are already seeing the benefits of investment towards innovation in the modular form giving a glimpse of the enormous potential that will open up in coming years.