The raw material potential of the Czech Republic ”

This article summarizes the information on raw materials in the Czech Republic. Although mining was significantly reduced not long ago, there are still rich deposits of ores, non-metallic raw materials, as well as energetic and construction ones. Many of them are potentially utilizable in future, especially those which are economically favorable, and their mining is not in any conflict with environmental interests. Deposits are distributed irregularly, and their raw materials are different in both the Bohemian Massif and Western Carpathians. In order to be complete, the text also comprises deposits, which are restricted by environmental limits or their mining promises a low-cost effectiveness. The article is amended with actual statistical data.


INTRODUCTION
Although the Czech Republic is rich of mineral resources, deposits are distributed very unevenly and subject to local geological structures. In the Bohemian Massif, the important deposits of gold, silver, copper, fluorite and uranium were extracted in the past; nowadays, brown coal, kaolin and construction materials (gravels, sands and aggregates) are dominant raw materials. The Western Carpathians are characterized by rich deposits of energetic raw materials, especially black coal seams, oil and natural gas. Gravel sands and brick clays are utilized as well. Black coal mining, however, is facing economic problems, especially not very transparent privatization process of Ostrava-Karviná mines. The main priority is damping the extraction without any clear concept of the state energetic policy. Any future mining in abandoned ore deposits is problematic -among main strategic raw materials, it is possible to regard only uranium and possibly lithium in the Krušné hory mountains or gold in the Kašperské hory mountains. The article concerns four essential groups of raw materials -ores, non-metallic raw materials, as well as energetic and construction ones. Statistical results are compiled in tables; those raw materials which have a little strategic importance are not comprised.

LITERATURE REVIEW
The Czech territory has a long mining tradition. There is a vast amount of literary sources on this theme, so only a small part of them could be utilized in this article. For example, Měchýř and Matějček (1987) inform about a lingering ore mining before the end of middle ag-es and show how specialists passed into newly opened collieries and coal pits. Cílek, Kotrba, and Majer (2015) describe the wealth of Czech subsurface; they also depict changes of scenery due to tedious mining. The online article by Měchýř and Matějček (1987) deals with the history of uranium extraction and its current status. Other authors interpret the actual situation in Czech mining and its possible perspectives. While Makarius (Starý et al., 2007) engages in legal aspects of mine working, Starý et al. (2007Starý et al. ( , 2010Starý et al. ( , 2016 publish annual reviews of raw material sources in the Czech Republic. The same kind of information is included in articles by the Czech Geological Service (ČGS). Smolová (2008) writes about mining in the Czech territory. Coal extraction is a special theme. Besides Měchýř and Matějček (mentioned above), some other authors deal with Czech coal deposits. Havlena (1964), as well as Roubíček and Buchtele (2002), follow both geologic and technical aspects of coal mining, while the article "Studium vybranych" (2008) studies working conditions and risks in the Upper Silesian basin collieries.

GENERALIZATION OF THE MAIN STATEMENTS
Czech mining is not in a very good condition now. The last ore mine was abandoned in 2016 and hard coal mining districts in the Bohemian Massif were in fact liquidated. The last one in the upper Silesian Basin is being damped. While there are promising reserves of uranium, lithium or other ores -as well as hard coal in Frenštát -any mining restoration depends on future economic conditions.

The potential of raw materials in the Czech Republic
As written above, the distribution of deposits within Czech state borders is very irregularwhile ores are bound to the pre-platform units of the Bohemian Massif, non-metallic materials (including energetic and construction ones) prevail in the platform sheet and Western Carpathians. Of course, there are some exceptions; black coal is predominately of the Upper Paleozoic age, but isolated deposits of hard coal are of the Cretaceous (Lower Cenomanian) origin (Havlena, 1964). An important secondary deposit of uranium in the Northern Bohemia is also of the Upper Cretaceous age.

Czech reserves of ores
There were about 180 mined locations of ores in the past -especially silver and other metals (Starý, 2007). In fact, there were significantly more mines. Their remnants are still visible in mountain terrains; unfortunately, reliable maps do not exist, and most medieval records are not fully clear (Měchýř & Matějček, 1987). Mining in the Bohemian Massif has a long tradition -gold was washed here in the 9th century B.C. and later pitmen extracted deposits of silver, tin, lead, copper, etc. During the period 1948-1989, deposits of ores were still economized, but then their mining rapidly decreased (Starý, 2007). In 1994, gold mining was finished in the Zlaté hory mountains (Starý, 2007), but the real end came as late as 2016, when commercial activities were stopped in the uranium shaft Rožná (Historie a současnost těžby uranu v ČR, 2017).  Table 1 does not include reserves of copper, silver and lead, because these reserves are not economically important. One large scale deposit of gold and tungsten is situated in the Kašperské hory and deemed the most perspective ore deposit in the Czech Republic (Starý, 2007), but the deposit is in collision with ecological intents (Starý, 2016). Mokrsko and Kutná hora are exclusive registered deposits of gold -nevertheless, their utilization is also blocked by environmental interests. Classical mining is uneconomic and utilizing the cyanide remains out of the question. A new perspective point of interest -lithium -could be mined at Cínovec (today abandoned). Exclusive registered deposits of tin have only poor ores; however, in future, they may become sources of rare elements -rubidium, cesium and tantalum. The Chvaletice deposit might become an important potential source of manganese (Starý, 2016

Reserves of non-metallic raw materials
In the past, three main raw materials were extracted in the Czech territory -glass sands, kaolin and graphite. No later than during the 13th century, glass sands were worked. Kaolin and graphite are mentioned in the 18th century; at the end of 19th century, the production was significantly increased by construction materials (ČGS, 2016). But generally, it is known that especially stone from local sources was widely utilized during the whole middle ages. Table 2 does not deal with other non-metallic raw materials, i.e. barite, fluorite (sometimes classed as ores), graphite, diatomite, quartz, feldspars and gemstones because their reserves are for the most part negligible. The largest economic reserves are formed by limestone, kaolin and clays; abundant amounts of gypsum are not considered strategic for its surplus production in the process of desulphurization. By contrast, kaolin is deemed a strategic material.

Reserves of energetic raw materials
Among main energetic raw materials are referred coal, oil and natural gas -the so-called fossil fuels. Within this category uranium should be mentioned as well, but it is a question of view. The Czech Republic disposes of considerable reserves of coal; uranium is regarded non-commercial (Starý, 2010). A possible future utilization depends on economic aspects; however, environmental interests play their role as well.
Regarding coal, there are huge reserves in the Czech territory; other categories are marginal (anthracite, lignite, bog) (Roubíček & Buchtele, 2002). The main amount of reserves appertains to black coal of the Carboniferous and Permian age. Seams were extracted from many locations in the Bohemian Massif. All these mines are abandoned (including rare deposits of the Cenomanian coal). Seams of hard coal are still worked in the Upper Silesian Basin. The material is well coakable, abundant and of good quality. The main problem is, however, the geology of this area and a considera-  (Starý, 2010) and its utilization in future is not certain -therefore, it is conserved. Geological reserves are estimated at 1,526 billion tons; 259 million tons are obtainable (Starý, 2016  Note: Table 3 summarizes reserves of energetic raw materials in the Czech territory (as on 2016).
worked in the Czech part of the Upper Silesian basin, but its economic significance decreases. The deposit in Frenštát is prospective but blocked because of collision of interests (the same is valid for reserves at Mšeno). Other hard coal deposits are not exploitable. Brown coal is mined in two separate basins in the North-Western Bohemia; however, significant reserves (almost one billion tons) are blocked by territorial mining limits. Mining the uranium deposits depends on a future state energetic policy.