My method

I did not take as many pictures as I would have liked, mainly because I was unsure of the wishes and restrictions (if any) of the people in charge of the project. More picture are available on the official blog site and elsewhere.
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The method I used was one that I felt happy with and which I thought covered the most soil.
I would start with a spoil heap and remove as many of the stone and rocks that I could see. This was because some of them contain enough mineral content to give me a reading, albeit at the lowest end of the scale. Once the rocks had been cleared away I would chose one end of the heap away from the end being used if the heap was still in use, and create a new starting point.

The spoil heap to begin with.


I would begin by detecting the entire surface area of the existing heap and then moving the soil nearest, to my new start point and depositing it to the left of the heap.

In progress

As the new pile got larger I created a gap between the two and maintained that throughout. When the soil was shifted from one heap to the other I would proceed to detect the new area exposed by it's removal, but also the soil that I had removed because any small item missed on the first swing may now lie in a different position which allowed it to be detected. This happened a few times especially with the smallest pieces of iron which were only 10 to 15 mms in length.


This heap is approximately half done and shows the new surface area on one side of the heap which enabled me to spread more soil over a smaller ground area. I then proceeded to detecting the entire surface of the new heap far quicker.

A smaller spoil heap in a finished state.


Showing to the right is the area left flat. This is done to be sure of not picking up any thing that might lay on the surface before the heap was deposited.
This was also left to enable any on-going heaps to be added to without mixing the new material with the old.
My future idea would be to detect an area before the spoil heap is created

The method was very successful and went on to produce approximately 40 assorted sized pieces of lead, copper alloy, iron and one more coin.