Map of oil shale mining history in Estonia
Oil Shale is Estonia’s prime mineral resource. Oil
shale is deposited in a single economic layer with thickness of 2,5 to 3 meters
in depth of 7 to 100 meters in area of 2700 km2. Its production
makes 70 percent of world’s oil shale production and two thirds of Estonia’s
total mineral production. Mining activity started in 1916, peaked in 1980 and
is ending in next 30 years. Therefore it is important to save oil shale mining
history in easily accessible database. The Mining Institute of Tallinn
Technical University has created geographically referenced database of oil
shale. MapInfo Professional is used for mapping geology and mining situation.
The map includes research and mining fields, mineral and overburden properties,
underground and surface workings. Additionally technological diagrams and data
are saved. For analysing underground mining influences, exact current mining
situation and previous situation is compared with surface topology in mined out
areas. Open cast mining results are compared with aerial photos and digital
base maps.
Both underground and surface oil shale mining started
by handwork. Analyses show that mining influence to the environment from this
period has been minimum. As technology developed and political situation
changed, the influence increased with raise of production capacity. The
conditions for starting of oil shale mining and promoting of development were
the war time fuel crisis, the lack of fuel mineral deposits, particularly of oil
deposits environs, the interest for fuels by Russia and Germany, particularly
for navy, good mining conditions and high quality of the oil shale, disengaged
labour. The favourable reasons for liquidating mining activities in Estonia are
elimination of interests of great powers, discovering of new oil and gas
deposits elsewhere and the development of transportation of fuel minerals,
deterioration of mining conditions, exhausting of best reserves and
environmental reasons.
General overview of the Baltic oil shale area
The reason for oil shale exploitation in the area of
former Russia was the crisis of fuel consumption in the time of World War I. At
the beginning oil shale was used as a local fuel. It displaced coal in heating
plants, locomotives, cement and lime furnaces. Oil shale mining began in
Estonia province in 1916 for supplying Russian capital Petrograd (now St
Petersburg).
First period. Permanent kukersite mining
started as soon as Estonia got its sovereignty in 1918. One of the oldest oil
shale enterprises, State Oil Shale Industry, was established. The private
companies formed almost at the same time and were owned by Estonian, as well as
by German, English, Swedish and Danish owners.
First fifteen years, all mines used strait works
technology, which meant handwork. First stripping shovels and locomotives
appeared in thirties. At the same time electric drilling began. Transition to
the mechanized mining began in fifties. After that, longwall mining, which was
widely used by Russian coal mining, was applied. For oil shale mining, double
unit face method was used. Mines applied cutters, conveyors, electric
locomotives and force ventilators. In all of the mines electrification was
started.
Second period. The technologies of oil
shale retorting that were used elsewhere in the world, failed because of local
oil shale properties and partly because of economic reasons. In Estonia
reliable, inexpensive and productive technology for shale oil retorting was
worked out at the beginning of thirties, during The First Estonian Republic.
Since 1937 shale oil export value exceeded import value of other fuels. So
Estonia achieved the independence in power what was the result of the
government policy. The arrangements made by the government for oil shale industry
were high depreciation rate, such as 20 per cent, relief inventory from import
tax and great export subsidy. This launched the progress of shale oil industry
in the Baltic Basin. Oil shale processing products became some of Estonia’s
essential export items. Forty five per cent of it was exported in 1938. The oil
shale products and shale oil accounted for eight per cent of Estonian export.
Oil shale petrol was also produced, in 1938 only 6.4
per cent of that were exported that formed 1.6 per cent in 1939 of total
Estonian export. The cement industry started using oil shale to improve the
quality and economy of cement production. Thanks to oil shale, Estonia became
independent of foreign fuel and energy.
By 1940, eleven million tons of oil shale had been
mined out and the annual production reached 1.7 million tons. After the World
War II, the soviet authorities immediately started to develop shale oil
processing, mostly for the Baltic Sea Navy and gas generation for the city of
Leningrad. The central station electric power industry started to develop in
Estonia in the 1950s. Several new mines were constructed and put into
operation, in 1950, the annual oil shale output was three and half million
tons, and by 1955 it reached seven million tons. The oil shale was used mainly
as fuel at Tallinn, Kohtla Järve and Ahtme power stations, at Kohtla Järve and
Kiviõli chemical plants and at Kunda Cement Plant.
Third period. Building and putting into
operation new power stations (Baltic Thermal Power Station in 1965, output 1400
MW, and Estonian Thermal Power Station in 1973, output 1600 MW) increased
remarkably the demand for oil shale. To meet these needs, two new mines and
three open casts were opened. At the same time four mines were abandoned. The
increase of mining capacity was rapid, from 9.2 million tons in 1960 to 17.5
million tons in 1970. Oil shale mining production reached its maximum level of
31.35 million tons in 1980. Building of the third thermal power station was
planned as well and due to this the annual output of oil shale mining was
planned to be 50 million tons.
Forth period. In 1981, Nuclear Power
Station was built in Leningrad province, which caused the decrease in
electricity demand in the north-western part of the former USSR. This led to
the decrease of oil shale production in Estonia, 29.7 million tons in 1980,
25.7 million tons in 1985, 21.2 million tons in 1990 and 12.1million tons in
1995. Prof. Reinsalu published the first scientific prognoses of the
inescapable decrease in oil shale mining in 1988. According to this, the
Estonian oil shale industry would vanish in the third decade of the next
century. Since the beginning of the 1990s, the consumption and export of
electricity had dropped in Estonia, as it has been in all East European countries.
Oil shale output decreased slowly and is now at a level of 10 to 12 million
tons in a year.
Ingo Valgma, M.Sc., PhD student
The Mining Institute of Tallinn Technical
University, Kopli 82, Tallinn, 10412, Estonia, Internet address https://www.ttu.ee/maeinst/
Phone: +372 620 38 50, Fax: + 372 620 36 96, E-mail: [email protected]