A RETROSPECTIVE OF THE HISTORY OF BROWN COAL MINING
The fi rst written record of apparent coal mining in the North Bohemian Brown Coal Basin dates back to the beginning of the 15th century. The town of Duchcov Chronicle has an entry, dated 21 May 1403, on the sale of mining works. The fi rst record of coal mining in the Most region dates back to 1613, when the Emperor’s privilege to mine coal near the villages of Havraň and Hrob was bestowed upon the resident of the town of Most, Jan Weidlich. The fi rst account of mining coal after the Thirty Year War comes from 1740 from the environs of the villages of Varvařov and Otvice in the Ústí nad Labem region. In the beginning of the 19th century (1803), the mining of brown coal in the then Litoměřice and Žatec Regions only reached 20,000 tonnes. By 1848 mining increased to 123,000 tonnes, because a considerable amount of what was mined was exported to Saxony via the Elbe waterway. The industrial development and expansion of coal mining in the North Bohemian Brown Coal Basin is associated with the building of the railway network in the region below the Ore Mountains from 1860 to 1870. In 1860, 546,000 tonnes were mined and that number constantly increased. During the period before World War I, mining reached its highest level in 1913, which was 18.607 million tonnes.
During the years of the fi rst Czechoslovakian Republic, around 15 million tonnes were mined annually and this number exceeded 20 million tonnes in the war year of 1943. After the drop in mining during the last year of World War II (in 1945 only 11.095 million tonnes), mining quickly grew as a result of Czechoslovakia being incorporated into the Eastern Block and Českosloits orientation on heavy industry and its growing consumption of electricity. The level of 50 million tonnes was surpassed in 1964 and the maximum mining of the North Bohemian Brown Coal Basin (NBBCB) was attained in 1984 when 74.653 million tonnes were mined. During the second half of the 80s and especially in the 90s, the mining of brown coal in the NBBCB quickly decreased. Electricity production was no longer dependent only on brown coal and in 1991 a government resolution was issued on territorial environmental limits on mining, which limited the mining of most active mines within the territory of the NBBCB. In 1999, mining dropped to under 35 million tonnes and in 2006 the total amount of mined coal was 38.586 million tonnes.
From 1860 to 2006, a total of 3,880 million tonnes of brown coal was mined, 2.923 billion of that was after World War II, averaging 47.15 million tonnes/year. Only 887.7 million tonnes remain in the territorial environmental limits for the mining operations of all of the current fi ve active mines, i.e. only 18.7 % of the total possible coal that could be mined from the NBBCB. Documented by the graph in Fig. 1.
During the last sixty years (1945–2005), it was necessary to conceal 7.5billion m3 of overburden after mining coal. The level of the removal of 100 mil. m3 of overburden was attained already in 1965 and the removal of overburden reached its maximum in 1989, i.e. 223,628 mil. m3. Currently, the removal of overburden averages around 100 mil. m3/year (109.9 mil. m3 in 2005 – see the graph in Fig. 2). The stated values result in a “overlay” ratio between the mining of coal and the removal of the overburden at 2.86 m3/t.
THE IMPORTANCE OF BROWN COAL IN THE DOMESTIC POWER ENGINEERING MIX
The importance of the North Bohemian Brown Coal Basin for the total level of mining brown coal and lignite in the Czech Republic is documented in the graph in Fig. 3.
From 1945 to 2005, NBBCB’s share of the total amount of coal mined was always above 70 %. During the last fi fteen years it came close to 80 % (79.8 % in 1995).
The Most region had, and has, the greatest amount of mining in the North Bohemian Brown Coal Basin. During the most productive period of mining in the basin, in 1984, 38.6 million tonnes of coal (51.7 % of the mining in the NBBCB) was mined in the Most District and 11 mines were in operation. Currently, that share is at almost 42 % and in 2005 mining in the Most region reached 16.1 million tonnes. Almost 13.2 million tonnes annually were mined in the Chomutov region and 9.0 million tonnes in the Teplice region. Coal mining in the Ústí nad Labem region was stopped in 1997.
After World War II, small quarries and underground mines dominated the North Bohemian Brown Coal mining region. Since the 1940s, large open-pit mining was carried out at the Komořany region mines, Obránců míru, Československé armády and Jan Šverma, At the beginning of the 60s, the Merkur openpit mine began operations in the Chomutov region. The development of the open-pit mine Maxim Gorkij (Bílina) began in the early 1970s. A total of 24 underground mines and 26 quarry mines were in operation, however, only seven of these mined more than 2 million tonnes/year. In the 1960s, mining reached its maximum in 1964 (40.2 million tonnes) and underground mines had their maximum (11.3 million tonnes) in 1961. The largest quarry operation in the 60s was the open-pit mine Jan Šverma that mined 8.028 million tonnes (1964) and the largest underground mine was Centrum with 1.126 million tonnes in 1965.
The graph in Fig. 5 documents the development of the total mining in NBBCB, the number of mining operations, and their average output during 1945 to 2005. In 1945, there were 59 mines in operation in the basin, 24 underground mines and 25 quarries. Together their output was 11 million tonnes of coal, which means the average output of one mining operation was only 188 000 tonnes/year.
With the development of open-pit mining their number constantly declined. In the middle of the 80s, only 5 underground mines and 12 quarries were in operation, with a total output of 72.8 million tonnes, and the average output of one mine reached almost 4.3 mil. t/year.
Currently in the Most region, there are 1 underground mine (Centrum) and 3 quarries (ČSA, Vršany, Šverma) in operation, the Chomutov region has the Libouš quarry, and the Teplice region the Bílina quarry. These 6 mining operations mined 38.4 million tonnes, which represents an average output of 6.4 mil. t/year per mine.
During the period of greatest output (1984 – 74.653 million tonnes), 12 quarries were in operation with a total output of 70.307 million tonnes (from this 8 open-pit mines with outputs from 4.5 to 11.5 million tonnes/year) and 6 underground mines with a total output of 4.346 million tonnes. The greatest output was achieved by the Březno (Libouš) quarry in the Chomutov reodgion (11.452 mil. t) and among underground mines the Kohinoor mine (1.574 mil. t). The tailings at Kopisty and Horní Jiřetín were recultivated, along with extensive land north of Teplice, after mining in the former Dukla mines (Barbora Lake) ended.
After 2000, mining decreased in connection with Government Decrees Nos. 331 and 444 from 1991 on Territorial Environmental Limits on Mining. After they were issued, the following quarries were closed in the 90s: Obránců míru (1994), Chabařovice (1997), Merkur (1998), and Most (1999), and three underground mines – Julius III (1991), and in 1992 Žižka and Alexander. In 2000, quarry mining reached 39.4 million tonnes and underground mining 0.5 million tonnes. The largest quarry mining operation was the open-pit mine Libouš (13.971 mil. t), and the underground mine Centrum had an output of 500 thousand tonnes of brown coal.
The graph in Fig. No. 6 documents the transition from small quarry mining and underground mining to open-pit continuous mining and conveyor belt transport.
At the beginning of the 20th century, underground mines accounted for more than ¾ of total output. Only at the end of World War II, thanks to the development of the open-pit mine in the Komořany region, did quarry mining dominate (51.5 %). From 1945 to 2005, the output of underground mines accounted for only 13 % of total output (373 million tonnes) and quarries accounted for 87 % (2,512 million tonnes). Underground mining will end in 2008 with the closing of the last mine, Centrum. The Czech Republic, as a result of the limiting of mining by the territorial environmental limits (TEL) from 1991, has available only 1,089 million tonnes of brown coal reserves that can be mined, of which the NBBCB has 888 million tonnes and the Sokolov region has 201 million tonnes. In the target year of the State Power Engineering Concept from 2004, i.e. 2030, the mining of brown coal will be 6.5 million tonnes lower than anticipated. After 2040, mining will decrease to only 6 million tonnes annually. This situation can only be reversed with the partial loosening of limits.
If limits are adhered to, the following quarries will gradually close: J. Šverma (2012), ČSA (2017), Bílina (2034), and Libouš (2038). If there is just a minimum correction of the territorial environmental limits, 287 million tonnes of extractable reserves can be acquired in the territory of the 2nd stage of development of the ČSA quarry and 120 million tonnes in the foreland of the Bílina quarry.
If the EU has a deep energy crisis in the 2nd half of the 21st century, the Czech Republic can off er the exploitation of three coal reserves in so-called reserve locations with 451 million tonnes of reserves and the continuation of mining in the ČSA quarry into the territory of the 3rd and 4th stages of its possible expansion with 486 million tonnes of reserves. The exhaustion of coal in the basin would thus be put off from 2054 to 2123.
This is obvious in the graph in Fig. No. 8. The loosening of limits at two quarries, ČSA and Bílina, would increase reserves by 407 million tonnes, i.e. by 37 % and would ensure, in the 2040s, mining at a level of 20 million tonnes, and therefore, at the consumption of 0.7 kg coal per 1 kWh, also the production of 28.5 TWh electricity annually. Mining could continue after 2060 at this level with the opening of three reserve locations at Zahořany, Podlesice, and Bylany, and the further advancement of the working front of the ČSA quarry to the Záluží pillar (3rd and 4th stages of expansion), up to 2120, but with a drop below 10 mil. t/year after 2080.
The state of recultivation after the end of mining activities within mining limits can be described in the following manner: The current active mining territory (125.5 km2) will expand to the extent of the territorial environmental limits, at the quarries of Libouš, Vršany and Bílina by another 13.2 km2, i.e. to 138.2 km2. The current area of recultivation (123.9 km2 as of the date of the issuance of Decree No. 272/2002 regarding the resolution of mining harm caused in the past) will increase to 272.2 km2. From this, 34.12 km2 apply to 6 new mining lakes (Libouš, ČSA, Vršany, Most, Maxim, and Chabařovice) and 238.08 km2 to forest, park, and agricultural recultivation. The most signifi cant recultivation measures that will be implemented gradually in the recultivated areas are a motor-racing circuit, hippodrome, airport, moto-cross, game preserves, arboreta, orchards, vineyards, multi-sports complexes, golf courses, etc.
It is obvious that if the State does not actively intervene, as the owner of the mineral wealth of the land, with a long-term concept, both brown coal mining regions in north western Bohemia are in their fi nal phase of mining. The exhaustion of coal reserves tied to territorial environmental limits sometime in the near future is completely unrealistic with regard to the manner of fi nal redevelopment of the remaining open-pit mines via hydric recultivation. The abovementioned analysis of the development of mining activities in the North Bohemian Brown Coal Basin can be considered, with a little exaggeration, as a nostalgic obituary of mining brown coal in Czech lands.