At Barton Mills the quarry is set in around 28 acres with over 1 million tons of reserves and planning to continue quarrying until the minimum end of 2042. Currently the quarry is producing over 30,000 tons per annum.
Since the closure of the Needham Market site, Barton Mills has had a massive investment of over £500,000.00 in a new plant to mill Chalk for industrial uses.
The main production process is via a tractor pulling a set of Simba X-press discs which loosen and break up the first 3 – 6 inches of Chalk, which is then collected by Caterpillar elevating scrapers. Once collected the Chalk is then deposited in a feed hopper feeding a disintegrator and a 15mm screen. All material is deposited on a large stockpile outside. Once we reach the peak of the hot weather we transfer a minimum of 10,000 tons into the main storage building for winter use. The material outside is naturally kept weatherproof and used for the Agricultural sector, with the material inside the building used for the industrial sector.
The process of milling the Chalk for the use in the industrial sector is what we call a double roll process. The Chalk is loaded into a feed hopper which feeds the first set of rolls before it passes through another set of rolls set at a 1mm gap. The advantage of passing the Chalk through rollers is you’re guaranteed a uniform product compared to screening, where you have a chance of contamination due to oversize, as well as it is very difficult to screen Chalk below 2.5mm. For special applications we pass the rolled product back through the mills to give a finer product and better passing between a 425 micron sieve and a 600 micron sieve.
The majority of the industrial Chalk is used in the brick industry; adding Chalk to the clay as well as other ingredients causes the brick to turn a yellow colour upon firing – the more Chalk, the yellower the brick is, but normally the CaC03 has to be 20% within the mix.
Barton Mills Quarry is also able to offer Chalk in 25kg bags in any grade (agricultural, 1mm, lump).
The average moisture content of the Barton Mills Agricultural Chalk is 12% and the Industrial Chalk is 12%.
CaC03 content is 98.2% (dry basis).
Single Rolled product passing a 1.18mm sieve is 99.6% and 97.5% passing a 600 micron sieve.
Double rolled product passing a 1.18mm sieve is 100% and 99.7% passing a 600 micron sieve.
Procedure for testing samples is 100 grams randomly taken from stockpile, placed in shaker bottle with warm water and shaken for 5 mins, sample then poured over 75micron sieve with running water and brushed till water runs clear, placed in oven for a minimum of 24 hours, once dry the sample is put in to the top of sieve stack and placed on sieve shaker for 1 minute.
Barton Mills Quarry
Chalk Hill Barton Mills
Bury St Edmunds
Telephone Numbers: 01638 713468 & 07843 95933