Whilst collecting information regarding these devices I came across a thread on the MINING-HISTORY web site from 1995 that suggests the term Buddle is a device where concentration occurs over a fixed bed, circular or rectangular. The Brunton used concentration over a moving belt and one of the authors could only find reference to Brunton's machine, Brunton's belt, Brunton's cloth or Brunton's frames so they may not be Buddle’s after all - but they are still an interesting and effective device

At Killhope these machines where used for separating lead ore from its matrix.
The body of the machine is a canvas belt which runs uphill supported by a wooden frame while a mixture of finely crushed ore and rock is fed onto the belt while a stream of water is fed from the top. The lighter rock is washed down the belt while the heavier particles of lead are carried up the belt and over the top to then be washed off the bottom of the belt into the collecting pit beneath. The belts where rotated by the 12’ water wheel and reduction gears. Both the wheel and the Buddle where fed from underground ducts operating by gravity from the sloping site so no overground launders where necessary.  The slurry in the feed box was agitated by a four armed paddle. Two units exist at Killhope although it appears there where four originally

The rate of flow was controlled by adjusting the tail end of the buddle to increase or decrease the angle by adjusting the 2 droprods