Geology and mineral resources of Bulgaria
Geology
Although Bulgaria is not a big country it has very diverse geology. The
tectonic settle of the country is presented mainly of four first-order tectonic units and
many second and third-order units. Included are the South part of the Moesian
platform, folded system of the Balkans, the Rila-Rhodopes massive and the SakarStranja zone.
These tectonic units include very diverse stratigraphic complexes ranging from
early Paleozoic, Mesozoic, Cenozoic and Quaternary. Their lithology comprise of
rocks with diverse genesis. At the surface sedimentary, volcanic and metamorphic
rocks are observed, holding different mineral composition and petrophisical and
geochemical characteristics.
Mineral resources
Regarding natural resources – every rock complex has its potential, which is
diverse too. For example in the North Bulgaria, in the Moesian platform, which is
build up mostly of sedimentary rocks, sedimentogenetic and hemogenetic resources
prevail. Now oil, salt, gypsum, phosphorite, manganese ore; limestone and marlstones
for the cement industry; sand and pebbles for building purposes; diverse clays for
making bricks; sand for the glass industry are produced.
The Balkanids’ zone is the most diverse one regarding the lithology and the
natural resources. In the West Balknids different types of ores (including polymetallic
ores, gold, silver, copper, molybdenum, a little Uranium etc) are produced. From nonmetal resources, different rock types and sands are important. They comprise mostly
of limestone with beautiful texture, some of them build up of shells, other with higher
density and differently colored – from black, to white and with hues of yellow and
gray. Despite of the tectonic reprocess they are eligible for big blocks to be gained at
relatively low cost. In that zone, some intrusive rocks are produced (granites with
rapakivi texture and redish hue, marble breccias and differently colored, mostly
Triassic, sands). In the region, there are many modern equipped factories for
processing that rocks.
In the Central part of the Balkanids mostly copper and copper-gold ore is
produced which is relatively poor in metal content, but its low price makes it valuable
for many foreign mining companies.
Of great importance for Bulgaria are the mines for black and brown coals in
the Central Balkan. The biggest open basin in the Balkan Peninsula for lignit coal is
situated in the East Srednogorie.
The Rhodope tectonic zone is rich of ores: polymetallic ore, lead-zinc ore,
gold and silver. Of great importance are the non-ore resources: marble, gneisses,
schists and tuffs with Paleogene age. There are some big findings of travertine that are
processed. Findings of zeolite and benthonite clay are basic for a whole branch of
Bulgarian industry – making filters for water and for the brewer industry.
The Sakar-Stranja zone is relatively weak studied. In the most Eastern part
Burgas’ mines are operating. Important for the region is the Elhovo’s finding of
brown coal. From non-ore resources important are some marbles with pink/gray hue
and some types of granites.
The abundance of mineral springs is a Bulgaria’s asset. Everyone of them has
its’ characteristics, but the water is, in general, appropriate for drinking and
competitive to other world’s distinguished waters.
Mineral Exploitation
In the recent years in period of transition from state planed economy to market
economy a lot of mines have been closed. The mines still in operation were privatized
with exception of coal mines. The only one oil and gas production company in
Bulgaria is also state owned. The main operating mines in Bulgaria are shown on
Fig.1. and described bellow:
CHELOPECH -
massive sulphide Au-Cu, underground,
165 t proven reserves Au, 3,5 g/t grade,
0,351 Mt Cu, 1,01% grade;calculated up to 600 m
below the surfaceELATZITE porphyry Cu-Au, open pit
123,4 Mt ore-0,416% Cu, 0,154 g/t Au
176,0 Mt ore -0,380% Cu
total resources - 650 Mt with 0,3%Cu
production 30000 t/d
ASSAREL porphyry copper, open pit
260 Mt proven reserves, 0,4% Cu grade
total resources 318 Mt, 0,359% Cu grade
production 9,2 Mt/y
MARITZA-IZTOK-
lignites, open pit, 2487 Mt reserves;
25,8 Mt/y production in 1996KREMIKOVTZI SEDEX iron - hematite, limonite, siderite
195 Mt Fe reserves with 31,5% grade;
24 Mt barite reserves with 44,2% BaSO4 ;
0,757 Mt/y Fe ore production;
0,216 Mt/y barite production;
MIROVO halite diapir, Permian age;
4357 Mt reserves with 71% NaCl content,
calculated up to 1500 m depth;
single drill-hole up to 4000 m resources;
1,6 Mt/y NaCl production as brines
NE BULGARIA
karst-hosted kaolin-quartz sands deposits;
172,8 Mt total resources and 1,2 Mt/y
production of kaolin
MAIN TYPES OF POTENTIAL METAL DEPOSIT
PROSPECTS•PORPHYRY Cu, Cu-Au, Au - Srednogorie zone, West Balkans
•MASSIVE SULPHIDE Cu,Srednogorie zone, Balkans
Cu-Au, Au-base metal
•MVT Pb-Zn-Ag
Forebalkan, Balkan ridge
•SEDIMENT-HOSTED
East Rhodopes, Strandja mountains
•DISSEMINATED Au
Balkan mountains
CARLIN TYPE&CARLIN LIKE
•EPITHERMAL AU VEINSEast Rhodopes, Balkan ridge,
WITH BONANZA
Kraishte region, West Rhodopes
•VEIN-METASOMATIC REPLACEMENT Pb-Zn-Ag Central
Rhodopes, Balkan ridge
LONG LIFE GUARANTEE PRODUCTION OF INDUSTRIAL
MINERALS•KAOLIN
- North-East Bulgaria
310 Mt total
`resources
•HALITE
- Varna region
6500 Mt
“•QUARTZ
SANDS
- North-East Bulgaria
83 Mt proven reserves
•BENTONITES
- East Rhodopes pred.
62 Mt total resources
•PERLITES
- East Rhodopes
24,5 Mt
“
•ZEOLITES
- East Rhodopes
2000 Mt
“
•CEMENT STONES- all the regions
2000 Mt
reserves
•BARITE
- Sofia region pred.
2200 Mt
reserves•DIATOMITES
- South&NE Bulgaria
2900 Mt
reserves•VERMICULITE - Sofia region
4,7 Mt total
resources
•GYPSUM
- NW Bulgaria,Danube r.
1116 Mt total resources
DECORATIVE ROCKS
LIMESTONE
MARBLE
GRANITE AND GRANIT DIORITE
QUARTZ MONCONITE
GABBRO, MONCONITE, ANDESITE
52 Mqubic m.
217 Mqubic m.
17 Mqubic m.
27 Mqubic m.
9 Mqubic m.
reserves
reserves
reserves
reserves
reserves
EXTRACTION IN 2000
COAL
OIL
GAS
27 Mt
0.04 Mt
15 M qubic m.
Fe ore
Cu ore
Au ore
Pb-Zn ore
0.6 Mt
23 Mt
0.6 Mt
0.5 Mt
KAOLIN
1 Mt
BENTONITE 0.3 Mt
BARITE
0.9 Mt
NaCl
1.7 Mt
QUARTZ SANDS 0.7 Mt
CEMENTS 3.5 Mt
LIMESTONE
MARBLE
GRANITE AND GRANIT DIORITE
QUARTZ MONCONITE
GABBRO, MONCONITE, ANDESITE
0.07 Mqubic m.
0.08 Mqubic m.
0.009 Mqubic m.
0.002 Mqubic m.
0.002 Mqubic m.
Past production activities and abandoned sites.
More than 42 uranium mining sites were closed in 1992 due to the economic and
environment reasons(Fig.2). The remediation of these sites is still in progress.
Fig.2 Uranium Production in Bulgaria