Behind the scenes at quarry with plans to expand
A quarry extension that could see gypsum quarried as close as 300 metres from homes and businesses will be strictly regulated, says the company behind it.
Formula, part of the St Gobain group, has planning permission to extend its activities at Bantycock Quarry open cast mine nearer to Fernwood.
It is consulting with nearby residents and businesses on how that will be carried out.
On Tuesday the Advertiser witnessed a blast from a viewing platform 300 metres from the detonation point.
There was no tremor underfoot and little audible sound, with the blast contained within the well of the quarry.
In preparation, 5.5-metre boreholes were sunk in the ground and 15kg of explosive charges lowered into each of them.
The soil was then re-packed to keep the blasts and the energy resulting from the detonations contained.
An 80-metre exclusion zone was enforced and, following a siren, the blast fired as three sets of ten, each creating a ripple effect as the ground lifted.
There was a gap of milliseconds between each detonation to minimise vibration.
Mr Jeremy Elvins, minerals estate manager, said due to the geology of the area the gypsum was close to the surface and the seams were too thin to mine underground.
He said unlike deep quarrying, the blasting was on a smaller scale because they did not want to shatter the rock.
“You get a raising of the ground,” Mr Elvins said.
“The shock wave fractures two layers of gypsum that we can get out with an excavator. “It is just enough to fracture the ground because we want the gypsum out in as large and manageable pieces as we can.”
Mr Elvins said because the blast was contained within the quarry, ground vibration may not be felt at all in homes and businesses at Fernwood, but a buffering of buildings by an airwave could happen if there was low cloud-cover and the wind was blowing in the right direction.
Vibrations in the ground are measured using digital seismographs set 300 metres, 400 metres and 500 metres away.
The results are monitored by Nottinghamshire County Council, which visits the site four times a year.
Following blasting, boulders of gypsum are picked up by excavators and carried on dumper trucks to be broken and crushed at a processing plant on the site.
The gypsum is then hand-sorted to ensure the best-quality mineral goes for specialist uses, and the rest to more general ones.
The quality gypsum is taken to the nearby Jericho Works, where more than 100 people are employed, to be processed into powder.
“There has been gypsum activity in this area for 100 years,” said Mr Elvins.
“It is mined here because of its purity. “A little piece of Newark is shipped all over the world.”
59 planning conditions regulate work
Bantycock Quarry, which employs around 50 people, covers 225 hectares and the deepest excavations are 43 metres below ground level.
Eight excavators, 26 dumper trucks, three bulldozers and one grading machine, which compacts the quarry’s dirt roads, are used, along with four frontend loaders for the crushing and sorting of gypsum.
Quarrying activity is subject to 69 planning conditions regulating blasting, dust, noise, operating hours and restoration.
Operations can continue until 2027, after which the site must be restored by 2029. That will involve returning the site to countryside through tree-planting, the creation of wildflower meadows and the addition of lakes.
Three have already been created on the Kilvington side of the quarry, where 180 species of birds have been logged.
In 2017, 300,000 tonnes of gypsum was quarried from Bantycock. The purity of the white gypsum from the quarry makes it of national importance.
It has specialist uses in ceramics, dentistry, medicine and food, and is exported as far afield as New Zealand. Coloured gypsum is used in more general ways in the agricultural industry and as an ingredient in plaster.
Silt that is washed from gypsum after it is quarried goes into cement.
Gypsum can be used in beer production to ensure consistency of taste, and to deaden the smell of ammonia on mushroom farms.