Thank you for sharing your experiences - quite fascinating.
Archaeology combined with historical sources can be quite fruitful. As
Tim has written GPR won't work with brine pits where salt is present but
one is always hopefull that new non-invasive techniques will work.
Details of the backfill were not specific and groundwater at
surface levels would be brackish. But I wonder what happens when you
have concentrated brine springs at the base of a pit which has been
filled in. Presumably the more dense brine would remain at the bottom.
I suppose, having been filled in that the springs would look for another
outlet - but that would depend on high tight and compact the fill is as
well as the water table.
On 1/24/04 5:20 PM Gaye Nayton writes:
>We knew the way the graveyard was supposed to work from historical sources.
>The plot plan and instructions for size and depth of shafts and the filling
>order that was to be used survives.
>The radar bounces off the top obstruction. Over an area containing I think
>from memory something like eighty shafts it bounced at three distinct
>depths, give or take a little for coffin collapse. Therefore the inference
>was the 10 ft shafts had been filled to different depths by multiple
>burials. However, they do not appear to have stuck to the filling order so
>that idea appears to have modified during the lifetime of the graveyard. A
>few of the shafts were even completely empty.
>The project I wrote about was a free trail for the National Trust who run
>the cemetery. It is too expensive for historical archaeologists in WA to
>use in the ordinary run of things, but that is because we don't get much of
>the pickings. It is well within the means of developers and government
>A engineering firm paid for me use it on the cemetery area outside the
>National Trust bit as the police department wanted to sell the area to a
>developer for dense inner city apartment construction. It did not work so
>well there as the area had been cut and filled to create level grass tennis
>courts. Bits of coffin, bones and brick rubble from brick lined shafts were
>massed in the filled area and dragged across the cut area too. It made a
>mess the machine could not make sense off so we had to rely on aerial
>The Rottnest Island Authority used it to find and map the graves of
>Aboriginal prisoners who had died at Rottnest Prison. It was also used in
>the search for the body of an Aboriginal elder whose head had been retrieved
>from a collection in England. But as they were not sure where he had been
>buried it was like looking for a needle in a haystack.
>As to your problem it would depend on what you backfilled your pit with. If
>it was the same dirt that came out you would probably be ok but if it was
>full of stones or rubble that would create problems I should think. It would
>be best to talk to a radar technician.
>----- Original Message -----
>From: "Bea Hopkinson" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Sunday, 25 January 2004 6:48 AM
>Subject: Re: Double decker graves
>> I was interested to read that you used a ground penetrating radar survey
>> which provided "pictures" underground. Could you do this for a 30 ft.
>> deep pit that has been excavated to 6 ft. and backfilled before
>> excavating to the bottom? And how could you tell they were buried at
>> different times ?
>> I was also wondering if this radar survey an expensive process ?
>> Bea Hopkinson
>> On 1/23/04 2:44 AM Gaye Nayton writes:
>> >Perth, Western Australia has them stacked three deep in our pioneer
>> >(Set out in 1830).
>> >The cemetery was planned so that they filled every second grave then came
>> >back and filled the missed ones. Then all shafts were filled they started
>> >again. The initial grave shafts were 10 ft deep.
>> >A ground penetrating radar survey I directed on part of the cemetery
>> >that they had not kept to the strict order of burial but some shafts had
>> >signals bouncing back from about 3 metres deep, others from about two and
>> >other shafts were filled to one metre below the surface. There was an
>> >lot of folks packed into 18 by 15 metres and only two headstones left in
>> >whole patch.
>> >----- Original Message -----
>> >From: "Jo Heron" <[log in to unmask]>
>> >To: <[log in to unmask]>
>> >Sent: Thursday, 22 January 2004 6:04 PM
>> >Subject: Double decker graves
>> >> Sorry to be late chipping on with this - double decker graves are
>> >> common practice in modern cemeteries, especially for families. My
>> >> grandparents were buried in the same grave, fifteen years apart and
>> >> my parents in another grave 5-6 years apart. Where the plot is for
>> >> two bodies, the grave is routinely dug an extra few feet.
>> >> Jo