In December 2008 Origin Alliance proposed construction of a concrete batching plant and other infrastructure on Lot 2 RP97625, a property known as Coert’s after the former owners, as part of infrastructure required for construction of the duplication of the Ipswich Motorway.  The proposal raised considerable concern with Jagera Peoples because of the considerable impact on the area, which also adjoins Goodna Creek.  While Coert’s property had a previous history of farming, followed by construction of a go-kart track, its proximity to Goodna Creek and the historical Redbank Rifle Range camping and water reserve indicated that there was a strong probability of considerable cultural heritage.

The project would involve stockpiling topsoil and then excavating in a cut and fill method to a depth of up to 4 metres in the southeast corner, with fill of the same height in the northwest corner.  It would totally impact on any surface and sub surface cultural heritage and effectively destroy any archaeological layers.  Origin Alliance agreed to a stringent mitigation program to recover all surface artefacts.  The program resulted in 20 new sites as defined by the Aboriginal Cultural Heritage Act 2003 being located.  A further 61 sites were later located during surface collections and monitoring making the area one of the richest in the whole Redbank study area.

In addition, a number of features considered to be Aboriginal clay ovens were located.  Turnstone Archaeology has had considerable experience elsewhere in identifying even residual ovens on the basis of criteria it has developed.  The main criteria involve the presence of a discrete circle of burnt clay under 1 metre and the presence of artefacts, charcoal and heat stones, such as broken grindstones or veiny quartz.  Specifically, baked clay that was used to cover the animal during cooking forms a highly resilient clay artefact similar to a clay tile that can last exposed to weather and climate for a considerable length of time, possibly hundreds of years.  While other similar artefacts can be formed by the burning of stumps and termite nests, they rarely form a consistent circle with associated baked clay.

A number of 6x10 m test pits were excavated as part of the mitigation program.  During the excavation of Test Pit 4, an Aboriginal oven was located in situ with a backed blade (Figure 1) wedged into the clay.

  Backed artefacts are comparatively rare and are useful artefacts for dating.  As a result Origin Alliance agreed to extend the time allowed so an extensive excavation could be undertaken by Jagera and Turnstone Archaeology to recover as much data as possible and possibly charcoal for dating purposes.  The Redbank microlith is an elongated blade-like flake with backing on one margin (Figure 2).  Backing involved supporting the flake on an anvil and carefully shaping one edge.  ‘Single-backed’ edges occurred when the retouching flakes initiated entirely from the artefact’s ventral surface.  ‘Double-backing’ occurred when point of anvil support was directly opposite the point where percussion force was applied; in this case flakes initiated from both the ventral surface and dorsal surface of the blank (Flenniken and White 1985).  The Redbank microlith is single-backed.  Backing a long, delicate flake requires exceptional technical skill to prevent the flake from snapping.  Dating was undertaken on three samples from Test Pit 4 and one sample from Test Pit 6 by the University of Waikato and funded by Department of Transport and Main Roads.  The dates were within the last 500 years.  TP4-C1 for example has a potential age of 163 years, ± 30 years, dated from 1950 (the date BP is used by archaeologists as a common date marker).  This would put it at approximately 1787 or just before European settlement in Australia began.  Charcoal from the base of the oven was carbon dated by the University of Waikato, New Zealand, to approximately 1700 AD± 300.  The artefact is asymmetrical in shape.  Asymmetrical microliths are sometimes referred to as ‘Bondi Points’ after specimens recovered near Sydney.  The slender proportions of the Redbank specimen differentiate it from most other microliths in the region, although a backed artefact with similar proportions was recovered from Maidenwell Shelter.

Construction of a haul road close to the existing Ipswich Motorway produced some of the most interesting finds in the whole project.

Thirteen new sites and a further 214 artefacts were located.  These included cores, flakes, retouched flakes and blades.  Several sites (Sites RK 166, 170, 173, 180, 182) contained European historical glass that had been reduced using traditional methods by Aboriginal knappers to make tools (Figure 3).  Dr Mark Moore (UNE) kindly provided a detailed analysis of these important post-contact finds (Figure 3).

The resulting analysis is significant in providing the first major comparative study of Aboriginal use of an introduced exotic material in the Brisbane-Ipswich area.

An excavation of one of these glass reduction sites (RK 180) resulted in the location of two Aboriginal stone hearths or fireplaces, the first recorded for the Brisbane-Ipswich area (Figure 4).  As a result of the excavation, Origin Alliance generously agreed to create a slight deviation in the motorway boundary, so the site could be preserved. A major report has been completed detailed the finds and mitigation program.