ANDS, MIN L ES F O & Y GICAL SU E R LO RV N O E T E Y E S G I R G N I Y M R E IA P R UB E LIC OF LIB The potential for iron ore in Liberia liberia ironore cover.indd 1 21/01/2016 09:37:17 Liberia – an under-explored West African iron ore region: ▪▪ A major historic iron ore producer — Africa’s leading producer in the 1970s. ▪▪ Approximately 65 per cent of Liberia is underlain by Archean rocks, the world’s main source of iron ore today. ▪▪ West Africa has world-class iron ore resources and is an expanding producer of global importance. ▪▪ Digital geological and aeromagnetic data available for the whole of Liberia. ▪▪ Significant potential for new discoveries in large, poorly known and under-explored areas. Iron ore in West Africa West Africa has numerous deposits and major important and widespread deposits are ‘banded resources of iron ore. Currently it accounts for iron formations’ (BIFs), most of which belong to a 15 per cent of African production with most mines Lower Proterozoic supracrustal sequence that rests located in supracrustal rocks in Sierra Leone, unconformably on crystalline Archean basement Guinea and Liberia (BGS, 2015). Various types of of the Man Shield, the southern part of the West iron ore deposit have been recognised. The most African craton that underlies much of the region. 13°W 12°W 11°W 10°W 9°W 8°W ! Wologizi Simandou Voinjama " ± " Foya ange e nge SIERRA LEONE ! i R GUINEA Rang N a N 8° Kpo Ra Wologiz 8° Nimb " Zorzor Western Range Mano to Cluster Western River Kpo To " ! @ Yekepa" Range Project Bea @ Sanniquellie Mountain ! Kitoma CÔTE D'IVOIRE N " N 7° " 7° " Iron ore producer Tubmanburg "! Bomi Hill Gbarnga ! " Bong Sacleapea Mount Tortro ! Iron ore deposit " Mofe ! H! Robertsport Central Liberian Plateau Iron ore occurence Creek Kakata Iron ore formations " @ St John Quaternary ?> " River South Pan African age province Goe Fantro Monrovia ! e Supracrustals n Putu Range Timbo Zo " Granitic to dioritic gneiss Zwedru N N @ 6° 6° Eburnean age province ?> " ear ! h Supracrustals Buchanan Buchanan S Intermediate to basic intrusions fines os ! st Putu Granitic to dioritic gneiss e C Liberian age province " Supracrustals Atlantic Ocean Cesstos City Granitic rocks River" Intermediate to basic intrusions Gbeh N N Granitic gneiss ?> " 5° 5° Granitic to dioritic gneiss Greenville " >? To wn Webo Hills @ Port 0255075100 Pleebo " Railway\former railway Km ! ! ! ?> " International boundary Harper 13°W 12°W 11°W 10°W 9°W 8°W The main iron ore deposits in Liberia and neighbouring countries. 2 liberia ironore.indd 2 21/01/2016 09:35:09 These BIFs have been recrystallized under regional considered to lie along the north-east-trending greenschist to amphibolite grade to form itabirites Cestos Shear Zone. An extensive Paleoproterozoic which comprise alternating bands of quartz, volcano-sedimentary sequence, the Birimian magnetite and/or hematite mineralisation. Perhaps Supergroup, is found to the east of the Archean most notable is the world-class Simandou BIF basement. The supracrustal rocks are surrounded deposit in south-east Guinea which has reserves by a regionally extensive granitoid complex. of over 1.8 billion tonnes grading 65.5% Fe and planned production of 100 million tonnes per In Liberia, the iron ore formations are generally of annum for a period of more than 40 years — this the itabirite type — metamorphosed banded iron is the sixth largest iron ore deposit in the world. formations. The three major metamorphic events In Sierra Leone the Tonkolili (Archean BIF) and recognised in Liberia, the 2.5–3.0 Ga Liberian event, Marampa (Neoproterozoic specularite) mines the 1.9–2.3 Ga Eburnean event and the Pan African opened in 2011, and ramped up to produce almost Orogeny (c. 550 Ma) resulted in the metamorphism 12 million tonnes of iron ore in 2013 (BGS, 2015). of the BIFs to itabirites (Kromah, 1974). Supergene In western Côte d’Ivoire the Mount Tortro and processes played an important role in the Mount Klahoyo BIF deposits are being developed. development of most high grade iron ores, notably at Goe, Mano River and Wologizi. These processes The Nimba Range has BIF resources in the Mount led to iron enrichment in a cap-rock, known as Nimba deposit in Guinea and in the Mount Nimba ‘canga’, which forms a blanket over the current or and Mount Gao deposits in Côte d‘Ivoire. In Liberia, paleo-surfaces of the itabirite. Canga refers to a the Nimba Range deposits, worked until the 1990s, breccia of weathered BIF and iron ore clasts that are are now exhausted. cemented by secondary Fe(III) oxides and hydroxides and are relatively resistant to weathering processes Although current production from the region (Harder, 1914; Schuster et al., 2012). is small in global terms, it should be noted that mining re-commenced as recently as 2011 in both Some minor components of iron ore, such as Sierra Leone and Liberia. There is little doubt that phosphorus, aluminium and manganese, may in the longer term, as global demand recovers and impact on the quality of the steel produced. In with improved security and political stability in the Liberia, limited data suggest that the phosphorus region, West Africa will become an increasingly content of some deposits is generally in the range important supplier of iron ore. of 0.05–0.10% which is slightly higher than ideal (<0.01% P) (Williams, 1986). However, as the iron The geology of Liberia ore deposits are generally of low- to medium-grade and suitable for blending, the phosphorus content Liberia is located within the Man Shield, part of can be readily managed to achieve acceptable the West African Craton, which comprises two concentrations. major areas of Archean and Paleoproterozoic rocks. Liberia was mapped during the 1970s in a joint Iron ore resources in Liberia programme between the Liberian Geological Survey (LGS) and the United States Geological Survey Numerous iron ore occurrences and deposits are (USGS). Aeromagnetic and aeroradiometric maps known in Liberia with most being BIF type (see for the entire country, supported by field checking, map). Of the eight major deposits, six are located were the principal source of information used to within the Liberian age Archean basement in interpret the geology. central and western Liberia while one is found in the Eburnean terrane in the east and another in Liberian age (2.5–3.0 Ga) Archean basement, the Pan African coastal belt. Historically Liberia extending across central and western Liberia, is was a major global producer of iron ore, being characterised by a granite-greenstone association the 7th largest in the world in 1980. Thereafter dominated by granitoid gneisses and migmatites. production levels declined until 1992 when the These are infolded with supracrustal metavolcanic intensity of the civil war led to the closure of and metasedimentary rocks and intruded by operations on the Nimba deposit at Yekepa. After a younger igneous complex. The boundary the cessation of hostilities and the establishment between the Archean and Paleoproterozoic age of a democratically-elected government in 2006 rocks (Eburnean age province, 1.9–2.3 Ga) is not there was revival of commercial interest in Liberia’s well defined in eastern Liberia, but is generally iron ore resources. China Union Investment 3 liberia ironore.indd 3 21/01/2016 09:35:31 Overview of operations at Yekepa. Photography by Jaco Boshoff for ArcelorMittal Liberia. Outcrop of banded iron formation. Photography courtesy of Tawana Resources NL. (Liberia) Bong Mines Company Ltd. (commonly located in one of two parallel bands of Archean BIF known as China Union) and ArcelorMittal were the with a north-east strike. Production commenced on first companies to start production. Production the Nimba deposit in 1963 and peaked at 12 million of ‘direct shipping ore’ (DSO) commenced in 2011 tons in 1974 but subsequently declined due to from the first of three deposits at Yekepa (Mount market conditions. Production started at Mount Tokadeh, Mount Gangra and Mount Yuelliton) in Tokadeh in 1985 to extend the life of the Nimba the ‘Western Range Project’ (WRP) operated by mine but operations ceased in 1992 with the ArcelorMittal. At present iron ore is mined from intensification of the civil war. two deposits, Mount Tokadeh in the WRP, which produced 4.9 million tonnes in 2014 (ArcelorMittal, The ArcelorMittal-owned mine at Yekepa is located 2015), and the Bong mine, operated by China about five kilometres west of the now exhausted Union, which recorded its first production of Nimba Range deposit. Production from the Mount 50 000 tonnes in early 2014. In 2013, Liberia was Tokadeh deposit at Yekepa, part of the Western ranked the 24th largest producer of iron ore in Range Project, is from high-grade oxidised ore, the world after just three years of production with an average iron content of 60–62%. This ore (BGS, 2015). only requires crushing and screening to make it suitable for export. Total ore reserves at Yekepa are Investment in the iron ore sector has led to 501 million tonnes at 48.3% Fe (ArcelorMittal, 2015). further developments of infrastructure such as the refurbishment of the Buchanan to Yekepa railroad Bong and the development of a new iron ore berth at the Buchanan port. Exploration activity for iron The Bong Mine is located about 110 kilometres ore in Liberia was until recently at a high level, with north-east of Monrovia and occurs at the western numerous exploration licences being held over the end of the north-west-trending Bong Range. The most prospective belts of supracrustal rocks that mine was operated by the Bong Mining Company form many of the mountain ranges in the country.