A review of the mineral potential of Liberia

Abstract

The Republic of Liberia in West Africa is underlain mostly by Precambrian rocks of Archaean (Liberian) age in the west and of Proterozoic (Eburnean) age in the east. By analogy with similar terranes elsewhere in the world, and in West Africa in particular, the geology of Liberia is favourable for the occurrence of deposits of a wide range of metals and industrial minerals, including gold, iron ore, diamonds, base metals, bauxite, manganese, fluorspar, kyanite and phosphate.Known gold deposits, mostly orogenic in style, occur widely and are commonly associated with north-easttrending regional shear zones. Gold mining commenced at the New Liberty deposit in western Liberia in 2015, while significant gold resources have also been identified at several other sites in both Archaean and Proterozoic terranes. Liberia has large resources of itabirite-type iron ores, most of which are located in the Liberian terrane, and was the largest producer in Africa prior to the onset of civil war in 1989. Production of iron ore is currently restricted to a single mine, Yekepa, in the Nimba Range. Other important deposits, some of them previously mined, include Bong, the Western Cluster, Putu and Goe Fantro. There is a long history of alluvial diamond production in western and central Liberia, together with more than 160 known occurrences of kimberlite. Most of the known kimberlites occur in three clusters of small pipes and abundant dykes, located at Kumgbor, Mano Godua and Weasua, close to the border with Sierra Leone. Many of these are considered to be part of a single province that includes Jurassic age diamondiferous kimberlites in Sierra Leone and Guinea.Deposits and occurrences of a wide range of other metals and industrial minerals are also known. Several of these have been worked on a small scale in the past, mainly by artisanal miners, but most are poorly known in detail with sub-surface information available at only a few localities. By comparison with most other countries in West Africa, the geology of Liberia is poorly known and there has been very little systematic exploration carried out for most commodities other than gold, iron ore and diamonds since the 1960s and 1970s. Further detailed field and laboratory investigations using modern techniques are required to properly evaluate the potential for the occurrence of economic deposits of many minerals and metals in a variety of geological settings. Digital geological, geochemical, geophysical and mineral occurrence datasets, including new national airborne geophysical survey data, provide a sound basis for the identification of new exploration targets, but in almost every part of the country there is a need for new and more detailed geological surveys to underpin mineral exploration.

Evaluation of Soil and Groundwater Quality at the New Georgia Open Dumpsite in Caldwell, Liberia

“…Generally, there was an increase in phosphate concentration soil to water. The lower mean values of phosphate recorded in the soil samples suggest that phosphate levels in the groundwater samples along the study locality do not originate from the dumpsite but may be due to background levels associated with the natural environment [26]. Phosphates are soluble in water.…”

Governing the artisanal gold mining sector in the Mano River Union: A comparative study of Liberia and Sierra Leone

“…The boom in production was interrupted by the civil war (1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) with plummeted output between 2010 and 2015 estimated at 18 500 oz. per annum (Gunn et al, 2018). The country's ASM sector is estimated to have some 100 000 miners, including diamond and gold subsectors (Republic of Liberia Ministry of Mines and Energy, 2020).…”

“…The gold reserve is estimated at three million ounces (Wilson et al, 2017). Growing attention of mineral exploration is directed to gold, and current licenses are distributed over the Archaean and Proterozoic terranes, with a concentration on major regional shear zones and belts of identified alluvial gold (Gunn et al, 2018). Mining activities fall within the scope of ASM, medium‐size domestic enterprises, large‐scale, and exploration companies, and 1142 (88.3%) of the 1293 mining operations are small‐scale artisanal operations (Wilson et al, 2017).…”

A Review of the Geology of Global Diamond Mines and Deposits

“…The alluvial deposits are similar to those in other parts of West and Central Africa and occur in high-and low-level terrace gravels, alluvial river flats and deep plunge pools within the active rivers and in the current river bed. Large gem-quality diamonds up to 170 ct as well as industrial diamonds have been recovered in diggings in west Liberia (Gunn et al 2018). At Camp Alpha in the northwest, diamonds exceeding 300 ct have been found in alluvial gravels (S. Haggerty pers.…”