Two Archaeologists use electronic trowels to excavate 12000 tonnes in 2 days



In March 2014 Heritage Detection Australia was employed by the Northern Territory Government to locate any metal artefacts which could possibly be associated with the discovery of a small bronze swivel gun at Dundee beach by Christopher Doukas in 2010.

The aim of the survey was to search a wide area in the vicinity of the Doukas find. Considering the discovery was in an intertidal zone, and is subject to storm and cyclone erosion it was essential for archaeologists to examine a large area quickly. While the approximate location of the gun’s discovery is known it was not possible to examine or excavate the exact location.

To ensure a large area was covered Zack Sheppard and I used ‘electronic trowels’ to ‘excavate’ 24000 square meters of Dundee Beach to a depth of 500 mm.

Using this methodology we were

  • Able to locate any metal object with a surface area of around 25mm x 25mm to 500 mm deep and beyond
  • Carry out a visual search of 24000 square meters of any non-metal cultural material on the surface

We did this in two days, or around 24 man hours and averaged an excavation of 500 tonnes or cubic meters of soil per hour. Metal objects down to the size of 12mm diameter were located and identified by the team.

How did we do this?

Of course there is no such thing as an ‘electronic trowel’ but if we had revealed this survey was carried out with metal detectors many archaeologists would never read this blog.

In fact some may be tempted to stop reading now … but think about what we achieved in such a short time. We located all the metal objects over 25mm x 25mm x 25 mm in 12000 cubic meters in two days and only disturbed a surface area of around 1 m x 1m of the beach while digging to identify metal objects.


Small fishing sinker identified at Dundee Beach. HDA image.


Zack Sheppard from HDA carrying out a grid search. HDA image.

Zack Sheppard and I were using the latest Minelab CTX 3030 metal detectors for this survey. These are our ‘electronic trowels’.

At the end of the survey we are convinced there are no large metal objects to be found within the search area and as we had our eyes on the ground as we gridded the area we were confident there was no surface cultural material either.

Modern archaeology is about efficient use of resources to meet the required outcome.

I challenge anyone to come up with a methodology in this scenario which was more efficient than what we achieved at Dundee Beach.

Of course, like all techniques, heritage metal detection has limitations. Very small metal objects cannot be detected at depth and buried non-metal cultural material cannot be revealed by the use of an ‘electronic trowel’.

Perhaps one day technology will take searching to a new level and a hand held tool will be able to identify all cultural material without excavation but at this time we can only identify metal.

If you are an archaeologist or heritage practitioner maybe it is time to consider the possibilities of using an electronic trowel …

Thanks to …

  • Christopher Doukas for making such an amazing discovery
  • David Steinberg and the heritage professionals at the Northern Territory for inviting us to assist
  • Mike Owen and the Past Masters
  • The Dundee Beach community who made us very welcome!
  • Minelab Electronics and Reeds Prospecting Supplies for their advice

For more info about the Doukas swivel gun go to the Past Masters Facebook page at



One thought on “Two Archaeologists use electronic trowels to excavate 12000 tonnes in 2 days

  1. I am an archaeologist and I use a MD. It is just another tool. It is what you do with it that matters. And, in Portugal, we have a group of MD’s who, supervised by archaeologists, do their and produce marvelous work on tertiary deposits.

    That said, no finds, uh? As we have been saying for the past years, there’s no Iberian ship there… 😉

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