Hillhead 2012
19 - 21 June 2012
International live demonstration show for the quarrying, recycling and heavy construction industries at Hillhead Quarry, Buxton, UK.
sound-intensity level
The intensity of sound, expressed in decibels above an arbitrary level, ie the rms pressure corresponding to the threshold of hearing, 20 x 10-6 N/m2.
The monthly journal for the quarry products industry.