grolleg porcelain
Imerys Minerals Limited
Imerys mines many materials from all over the world; their kaolin mines are found in Brazil, the United States, the United Kingdom, Ukraine, Australia, and New Zealand. English China Clay, as the name states, is mined near Cornwall, England. Their refinery is seemingly near this mining location, as is their home office and distribution center in Cornwall.
The kaolin consumer market is separated into three main groups: filler and paper coating accounts for 50% of all kaolin production, 20% is used in rubber coatings, paint, and plastic, and the final 30% is used in the ceramic industry, with most of the export going to Europe, the Middle East, and Asia. Imerys is the number one producer of kaolins for paper and sanitary ware in the world, and the number two producer of kaolins for fiberglass.
Kaolin Mining
More often than not, china clay is extracted from granite deposits using a “wet-mining” process. High pressure jets of water erode and wash out the kaolin, which remains suspended in a slurry. As the slurry travels to the bottom of the pit, it is pumped to the surface for processing. As the face of the pit’s kaolin reserves run out, ripping, drilling, and blasting of granite are used to access the reserves underneath. Dry mining has been employed in some areas of Cornwall, allowing for more selective extraction, which reduces energy cost and waste. Dry mining consists of removing chunks of granite from the pit face, then moving them to a processing facility to be treated in the same way as wet-mining, only on a smaller scale.
Thankfully, with growing demand for more kaolin in paper products and sanitary ware, wet-mining and other wasteful practices are becoming less economical and reducing profit margins, prompting kaolin production companies to cut back and find more economical, and in turn, environmentally conscious ways of producing.
One of the greatest concerns with clay mining regarding environmental degradation is particulate matter produced by mining and refining. A study with Imerys Materials specifically found that 61% of the particulate matter in the china clay mining area of Cornwall was attributed to Imerys mines. This particulate matter did not exceed the UK National Air Quality Strategy standards, but the effects of exposure to particulate china clay are under review.
Sustainability
This statement from Imerys outlines their current sustainability practices:
“We implement environmental management systems (EMS) at our sites to ensure we have a robust process to guarantee compliance with local regulations, and to identify, reduce and manage the significant environmental aspects and impacts associated with our activities. Then we audit our performance against the EMS’s targets. Most of our processes are primarily physical (crushing, milling, and sorting) but we use some thermal processes such as calcination and fusion. Our work produces impacts such as industrial waste and wastewater, hazardous waste and air emissions. We minimize the amount of waste we produce and carefully manage all wastewater discharges.”
Production of English China Clay from Cornwall peaked in 1988 at 2.78 million tons produced, and has seen a decrease since that peak due to competition with Western European paper markets importing from the Amazon basin. It is estimated that in 2016, reserves of china clay in Cornwall exceeded 60 million tons, enough to last 50 years with current production rates in existing pits.
Route
Imerys mines kaolin in Cornwall, England. The refinery is very near the quarry, so the raw material does not travel far to be processed. In 2020, Imerys partnered with IMCD to expand their distribution in the U.S. and Canada. IMCD’s U.S. office is located in Cleveland, Ohio. If we assume this material arrives to the U.S. through the New York Harbor, it travels 4241.2 miles from Cornwall to the U.S, 500 miles to Cleveland, Ohio, then 2330.7 miles to City of Industry, California to Laguna Clay Co., 1157.6 miles to Helena, Montana to Archie Bray Foundation Clay Business, and 113 miles to Missoula, Montana to the University of Montana. Grolleg porcelain travels 8342.5 miles to reach UM’s ceramics department.
To see these locations on a map, and aerial views of the mine and refinery, click here.