Geology and mineral resources of Bulgaria

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 Sakar-Stranja 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.

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 diverseone 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 non-metal 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.

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 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 to600 m below the surface

ELATZITE - 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 1996

KREMIKOVTZI - 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

oPORPHYRY Cu, Cu-Au, Au - Srednogorie zone, West Balkans

oMASSIVE SULPHIDE Cu,- Srednogorie zone, Balkans

oMVT Pb-Zn-Ag Forebalkan, Balkan ridge

oSEDIMENT-HOSTED - East Rhodopes, Strandja mountains

oDISSEMINATED Au - Balkan mountains

oEPITHERMAL AU VEINS- East Rhodopes, Balkan ridge,

WITH BONANZA Kraishte region, West Rhodopes

oVEIN-METASOMATICREPLACEMENTPb-Zn-Ag- Central Rhodopes, Balkan ridge

oKAOLIN - North-East Bulgaria 310 Mt total `resources

oHALITE - Varna region 6500 Mt "

oQUARTZ SANDS - North-East Bulgaria 83 Mt proven reserves

oBENTONITES - East Rhodopes pred. 62 Mt total resources

oPERLITES - East Rhodopes 24,5 Mt "

oZEOLITES - East Rhodopes 2000 Mt "

oCEMENT STONES- all the regions 2000 Mt reserves

oBARITE - Sofia region pred. 2200 Mt reserves

oDIATOMITES - South&NE Bulgaria 2900 Mt reserves

oVERMICULITE - Sofia region 4,7 Mt total resources

oGYPSUM - NW Bulgaria,Danube r. 1116 Mt total resources

More than 42 uranium mining sites were closed in 1992 due to the economic and environment reasons. The remediation of these sites is still in progress.