Natural Resources:

Oil, bauxite, low-grade iron ore, calcium, natural asphalt, mica, clays, salt, and hydropower. oil, some coal, bauxite, low-grade iron ore, calcium, gypsum, natural asphalt, silica, mica, clays, salt, hydropower http://www.state.gov/r/pa/ei/bgn/3166.htm
Production levels: http://www.indexmundi.com/minerals/?country=hr&product=ammonia&graph=production
Oil
Croatia has some limited oil and gas resources located southeast of Zagreb, along the Hungarian border and the Adriatic Sea. It led the relatively oil-dry region of southeastern Europe with oil production estimated at approximately 24,000 barrels per day (bpd) during 2007 while consumption was estimated at 102,000 bpd.
Most of Croatia's oil is imported via the Adria pipeline, which runs from the Adriatic port of Omisalj eastwards to Sisak, where it splits into a northern route to Hungary and an eastern route to Serbia. Proposals have been made to link the Adria pipeline with the Druzhba (Friendship) pipeline, which currently transports Russian oil westwards into Hungary. Under the new proposal, flows in the Adria pipeline would be reversed so that the port of Omisalj would begin exporting, not importing, oil. Pipeline links via Romania also have been proposed.Some analysts expect that the Adria pipeline could begin transporting roughly 100,000 bpd of Russian crude in the short term with an ultimate capacity of approximately 300,000 bpd. The South East European Line (SEEL) would transport 660,000 bpd of oil from the Romanian port of Constanta on the Black Sea to the Italian port of Trieste on the Adriatic Sea.The pipeline would be used mostly to provide oil to the countries along the route. Several alternatives exist for the route, with the southern route passing through Serbia and Croatia on the way to Slovenia and Italy. In November 2003, the Hungarian oil and gas firm MOL completed the