Chromite Ores

Hoxha, L. Structural control of Bulqiza chromite deposit: a case history

Journal of Alpine Geology, 48. S.37-44, Wien, 2007

Abstract

The world famous Bulqiza ultramafic massif, in the eastern  belt! of the Albanian ophiolites, has produced about 20 Mt chromite ore averaging 35% Cr2O3 and is the host to the remaining resources and reserves of high grade ores.

Traditionally, previous geological reports have described the form of the massif as an “eastward overturned anticline" a “’monocline structure", or more recently as a “ diapiric structure". The structural control is of essential importance to the distribution of the  mineralization, especially for northward extension of Bulqiza chromite deposit. This paper is based on a thorough generalization of previous exploration and mining data, and field observations. It is demonstrated that  the location of the Bulqiza eastward overturned chromite antiform is conformable with planar flow structures of the homocline  massif, and this is a useful guide for further exploration to the north of the boundary of  the known mineralization.

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POLYPHASE TECTONICS AS TOOL FOR EXPLORATION OF CHROMITE ORES HOSTED BY ULTRAMAFIC ROCKS OF BULQIZA ULTRAMAFIC MASSIF, ALBANIA

HOXHA, Lirim, General Administrator, Empire Mining Albania, Rr. Kongresi i Lushnjes, Pall. 33/2 #13, Tirana 00001 Albania, lirimhoxha@gmail.com

The Albanian ophiolites of the Mirdita Zone represent remnants of Mesozoic oceanic lithosphere within the Dinaride-Albanian- Hellenide segment of the Alpine orogenic system.

Most recent studies distinguish two different rock associations forming the Western (WOB) and Eastern Ophiolite Belt (EOB).

Bulqiza Ultramafic massif that covers an area of c. 350 km2 hosting the principal mined ores (Bulqiza-Batra, Thekna etc. with more than 22.6 Mt @ 40% Cr2 O3) belongs to the Eastern Ophiolite Belt (EOB).

The ores are considered as podiform chromite ores characterized by relatively small sizes, irregular shapes and limited lateral continuity.

In the structural point of view Bulqiza-Batra chromite deposit is widely accepted to be hosted by an overturned antiform, with easterly vergence, 4.5 km long, 1.2 to 1.5 km wide and 0.5 to 1.7 km down dip with an axial orientation strike 330 0. The antiform was thought to be restricted to the east by a southwesterly dipping normal fault over an area 3.8kmlong and 0.25 km wide (Bulqiza-Batra geologists). More recently are described steep southwesterly dipping normal faults at west limb and east directed thrusts at the eastern limb of anticlinorium (e.g Happel et al., 1998).

Exploration works performed by Empire Mining Corporation at Bulqiza-Batra-Thekna ore field and NW at Qafe Burreli carried out during 2008-2011years indicated for high developed west directed polyphase thrusting tectonics that led to new interpretation of the structural setting of the chromite mineralization in the Bulqiza-Batra-Thekna system- the secondary fold within west dipping homocline displaced by thrust faults, with eastern and western extension of chromite ores.

Northeastern Section - 47th Annual Meeting (18–20 March 2012) 

General Information for this Meeting

Structural setting of the chromite mineralization in the Bulqiza-Batra system- secondary fold within west-dipping homocline displaced by thrust faults (Hoxha, 2009)

(Hoxha, L. Structural control of Bulqiza chromite deposit: a case history Journal of Alpine Geology, 48. S.37-44, Wien, 2007)

The  analogues fold (anticline-syncline) with very high grade chromites at its core fold, and west limb and east limb extension is proved at  Thekna Lindore, that needs to be explored further.

Session No. 44

Mineralogy, Igneous, Metamorphic Petrology, Volcanology

Hartford Marriott Downtown: Ballroom E

8:00 AM-12:00 PM, Tuesday, 20 March 2012

Geological Society of America Abstracts with Programs, Vol. 44, No. 2, p. 103

Bulqiza Ultramafic Massif- At the valley has been the  chromite outcrop of Bulqiza Deposit. Actually, still are mining some small companies

Northern part of Bulqiza  Ultramafic Massif, Albania

Batra Valley- Southern part of Bulqiza-Batra chromite deposit. At upper part, an active open pit mine. At lower part Chromite Dressing Plant

• Lirim Hoxha, Ferro-Alloys Industry of Albania: issues and prospects, Center of Geophysical & Geochemical Exploration, Tirana, Albania (oral presentation at 12th International Ferro-Alloys Conference: Swissôtel, The Bosphorus, Istanbul, Turkey 17th-19th November 1996 14 pages.