Technical description of the mine site

The Beginnings of Clay Mining

KERAKER began its operations in 1991 as a sole proprietorship. At the start, the company dealt with the distribution and trade of ceramic raw materials, glazes, clay bodies, machinery, kilns, and tools.
In 1997, an opportunity arose: the clay mine in Kishajmás, owned by the Sásd Agricultural Cooperative (MGTSZ), was put up for sale. This mine had supplied high-quality clay to the cooperative’s ceramic workshop, which primarily produced folk ceramics, decorative items, and everyday pottery, employing over 100 people at its peak. After the political transition, the manufactory—like many similar ones in Hungary—collapsed under cooperative management, and both the workshop and the mine were privatized and sold.
In 1997, we purchased the mining rights to the Kishajmás clay mine and the forested areas belonging to the then-inactive mine.
In 1998, using exploratory drillings, we expanded the area suitable for mining and acquired the forest land necessary to start mining activities.
We laid out the mining plot ("bányatelek"), marking the final area of the clay mine.
In 1998, we prepared the mine’s Technical Operating Plan (Műszaki Üzemi Terv), and with approval from the Mining Authority (Bányakapitányság), we commenced mining operations.

The mining plot is located in Baranya County, within the administrative area of Kishajmás, on land registry parcels 0133, 0134, and 0166/2.
Mining is carried out by surface mining, creating terraces on the terrain, excavating them with suitable bucket excavators.
We load the clay onto transport vehicles and deliver it to the processing site.
In order to extract clay of the proper purity and quality, we first remove the forest above it, remove the stumps, deposit the humus layer separately, and deposit the transitional clayey layer onto a waste dump.
From the perspective of ceramic production, the useful mineral raw material lies in layers.

• The uppermost layer is reddish-brown in color, extremely plastic, fires bright red at 1000 °C, and retains its red color at 1200 °C. It can be used for ceramics only when significantly tempered.
• The middle clay layer is yellow, adequately plastic, suitable for producing red ceramics.
• The bottom clay layer is grey, fires pale red at 1000 °C, less plastic than the previous layers, and suitable for ceramic production.

During mining we extract the yellow and grey clay layers together, mixing them during excavation; by processing this mixture we produce the “Kishajmás pottery clay.”
We transport the extracted clay to the processing plant using transport vehicles, and deposit it there.

Geological Conditions of the Mineral Occurrence. Quality of the Mineral Raw Material.

The area lies south of the village of Kishajmás in Baranya County, on the northern side of Újhegy. The highest elevation in the area is the triangulation point on the hilltop at +245.8 m a.s.l., the lowest is +142.5 m at the wall tap next to the church in the village. The distance between the two points is 550 m.
The north-facing hillside is strongly dissected by erosion, which appears in sharp and deep gullies branching into each other, with narrow ridges between them.
Both agricultural land and forests are found in the exploration area.
The erosion bases are the valleys south of Újhegy, especially Pusztavölgy, which has a permanent stream running along its bottom. This stream flows into the Orfű Creek east of our area, which then carries the surface waters of part of the Hegyhát and the Mecsek northward toward the Kapos. The side valley containing the village is only 600 m long and is bordered by steep sidewalls.

The Pécs–Dombóvár railway line and a secondary road run through the Baranya-channel valley. The exploration area can be reached on foot from Kishajmás through a steep ravine, and by vehicle via the difficult dirt road accessing Újhegy from the south.

The area contains formations of the Miocene Budafa Formation (Mánfa Member), the Tari Formation, the Tekeres Formation, the Pécsszabolcs Formation, and the Upper Pannonian Transdanubian Supergroup.

A large part of the map sheet area is covered by Pannonian sediments. They lie discordantly on the basement, and the entire sequence belongs to the Transdanubian Supergroup. Three main facies types can be distinguished in the mapped area: near-shore and coastal facies, more closed quiet-water sub-basins, and the distant basin-center facies typical of southern Transdanubia.

For our exploration, the second type—the sub-basin quiet-water environment—is the most important, as the mineral raw material to be explored was formed under such conditions.

This facies occurs in the Bodolyabér syncline, between Korpád and Hetvehely, and on Öreghegy between Kishajmás and Kisbeszterce (NW of our area). Fine-grained marly, silty, clayey sediments were deposited discordantly on a dissected basement, and the basal conglomerate is missing.
Differences between the facies result from varying erosion areas and deposition conditions. Our area also contains numerous clayey interbeds, which favoured clay accumulation.
During the Pleistocene, loess formation was typical; in the Holocene, slope deposits formed, and erosion and landslides were significant landscape-forming factors.
 

Tectonics

In the exploratory drillings fracturing was observed in the greenish-grey clay layers, together with limonite coatings and manganese dendrites. However, many causes may explain this, as the deeper blue-grey and dark-grey clays did not show this fracturing. The most likely explanation is that after the sedimentary basin filled and became dry land, exogenic forces and surface movements caused the fracturing.
The Upper Pannonian green and bluish-grey clay sequence dips distinctly toward the W–NW.
In summary: the clay occurrence is lens-shaped in the overlying yellow–reddish-brown sequence, and layered in the greenish and bluish-grey sequence, and erosion modified it on the north.
To establish the mining plot, exploratory drillings had to be carried out, and samples taken from the drilled holes were examined by geologists. Their physical and chemical properties were tested in a laboratory. Based on the tests, it was determined that the clay is suitable for ceramic production and that a sufficient quantity is available for establishing the mining plot.