Annex 1: Greenland mineral deposit descriptions TABLE OF CONTENTS CHROMIUM ........................................................................................................................... 3 COPPER ................................................................................................................................. 5 GRAPHITE .............................................................................................................................. 8 IRON .................................................................................................................................... 10 NIOBIUM AND TANTALUM .................................................................................................. 13 PGE ..................................................................................................................................... 15 REES -WITH FOCUS ON ND/DY ........................................................................................... 18 TUNGSTEN ........................................................................................................................... 21 ZINC .................................................................................................................................... 23 CHROMIUM Greenland potential - Where in Greenland is chromium found and where is the potential 1. In Southwest Greenland about hundred kilometres south of Nuuk, the Fiskenæsset stratiform anorthosite complex occurs, with a combined strike length of 200 km. The complex stretches from the coast to the edge of the Inland Ice and is likely to continue under the Ice Cap. The anorthosite complex has been metamorphosed in amphibolite facies and locally up to granulite facies. The complex has furthermore suffered several phases of deformation, whereby the complex has been broken up in sections ranging from kilometres down to a few tens of metres in length. Chromium occurs in the mineral chromite, which is the dominating mineral in chromitites. Other minerals in chromitites are hornblende and plagioclase locally pyroxenes. Sulphides are rare in chromitites. Chromitite bands occur in nearly all stratigraphic units of the anorthosite complex. Most commonly chromitite bands are found in anorthosite and gabbro anorthosite, but chromitite is also found in several ultramafic units. The width of the chromitites ranges from centimetres up to a few metres. In fold closures up to 20 metre thick chromitite bands are seen. Composition of the chromite concentrates from 168 analysis varies considerably: Cr2O3: 27-35%; FeO (total iron): 33-42%; Cr/Fe ratio: 0.60-0.93. The general low Cr/Fe ratio shows that the chromitite is not metallurgical ore. Rutile (TiO2) occurs frequently as inclusions in chromite amounting up to 0.35%. If mining of chromitite takes place, rutile may be a valuable by-product (Ghisler 1976). 2. At Ujaragssuit Nunât some 150 km northeast of Nuuk a small body of ultramafic rocks occur embedded in gneisses. The ultramafic intrusion displays a complete magmatic evolution with seven cycles from dunite through harzburgite to gabbro anorthosite. Chromitite layers up to ten centimetres thick each and metre thick chromitite pods are seen. The presently exposed width of the intrusion is ~45 metres and length is ~150 m. Chromite makes up 90 vol. % of the chromitite pods and less in the chromitite layers. The chemical composition of chromite gave the following ranges: Cr2O3: 22-49%, FeO (total iron): 24-51%. Cr/Fe ratios and range was not determined (Appel et al. 2002). 3. The Seqi Olivine deposit which is located around 100 km north of Nuuk in southern West Greenland is a fairly large dunite body (around 100 Mt) that has been exploited for olivine from 2005-2009. The deposit has earlier been explored for chromite by the Cryolite Company in the 1960’ies. However, the company closed down decades ago and the reports describing their findings have since been lost. The deposit thus might have an undiscovered potential for Chromium. - Known resources and reserves of chromium in Greenland The chromium potential of the Fiskenæsset anorthosite complex was investigated in some detail in the 1970 to 1980’ies by the Canadian junior company Platinomino. No drilling was undertaken. On the island of Qeqertarssuatsiaq a fairly continuous chromitite band with width ranging from 1 to 7 metres can be traced for ~1400 metres. The estimated tonnage of this occurrence is of 2.5 Mt of chrome ore. For the whole anorthosite complex an estimated 100 Mt of chromium ore may be found. Layered Archaean anorthosite with layers of chromitite. from the Fiskenæsset anorthosite complex The chromium potential of the chromitite banded intrusion northeast of Nuuk is, from an industrial purpose, slightly more attractive than the chromite in the Fiskenæsset anorthosite complex. However, size of the intrusive body is much smaller. The intrusive body was heavily deformed so there are likely extensions of the intrusions in the general area, but they have not been found yet. - Overview and status of projects exploring for chromium Only very limited exploration has been carried out for chromium in Greenland during the last thirty years. While the world market for chromium seems to be well supplied, the exploration and the development of some of the known chromite resources in Greenland might be triggered and led by their interesting PGE contents. - References Appel, C. C., Appel, P.W.U. & Rollinson, H.R., 2002: Complex chromite textures reveal the history of an early Archaean layered ultramafic body in West Greenland. Mineralogical Magazine Dec. 202: vol. 66(6); p. 1029-1041. Ghisler, M., 1976: The geology, mineralogy and geochemistry of the pre-orogenic Archaean stratiform chromite deposits at Fiskenaesset, West-Greenland. In: Borthcert, H. (ed) Minograph Series on Mineral Deposits, Borntraeger 126 pp. COPPER Greenland potential - Where in Greenland is copper found and where is the potential Although underexplored, many parts of Greenland could hold a good potential for undiscovered sediment-hosted copper deposits. Sediment-hosted copper deposits account for c. 23% of the world’s copper production and known reserves. They are also important sources of silver and cobalt, and some deposits are also produce other metals such as lead, zinc, uranium, gold and platinum-group metals. Sediment-hosted copper are formed in basins that contain large sedimentary formations of marine or large-scale lacustrine (lake) environments. In Greenland, 40% of the ice-free landmass is made up of such environments and several smaller occurrences of copper are known. However, the larger ones remain to be found. Especially the sub-type, ‘Reduced-facies Cu’ deposit type, of sediment-hosted copper is important as they characterized by good grades of 1–5% Cu and tonnages between 2.5 to above 450 million tons. This type of deposit is sometimes also referred to as the Kupferschiefer-deposit after the type examples within a large sedimentary basin in Poland; a basin that formerly were interlinked with similar basins in East Greenland were similar, but smaller, copper occurrences also are known. Also the important copper deposits in DR Congo are of a similar deposit type. Two other sediment-hosted copper sub-types, the so-called ‘Redbed Copper’ and ‘Revett Copper’ are found in Greenland; however, these constitute normally lower grades and lower tonnages. The other main source of copper world-wide is ‘Porphyry-type deposits’ which constitute two-third of the world’s copper. However, the potential for this type of deposit is thought to be smaller in Greenland as the typical geological environment of this type of deposit is not present and as the crustal-exposure level in Greenland is too deep compared to areas elsewhere in the world that contain the major copper porphyry-deposits. Copper is also produced as by-products from igneous nickel-deposits. - Known resources and reserves of copper in Greenland Very limited exploration for sediment-hosted copper mineralisation has been carried out in Greenland. However, the activity that have been carried out have, mostly based on traditional surface-prospecting on exposed rock, successfully identified several smaller copper occurrences throughout many of the sedimentary basins in Greenland. Only a few of these have been investigated in detail to a level which allow for a geological estimate of overall tonnage and grade and none of these, are of economically viable. Distribution of tracts with sedimentary successions that are regarded as having potential for sediment-hosted copper deposits in Greenland. From Stensgaard et al. 2011. A first estimate of undiscovered resources in Greenland is included in the table below. The undiscovered copper resource estimates are derived from a statistical simulation which used globally tonnage/grade models for known deposits worldwide and bids on number of undiscovered sediment-hosted copper deposits within different sedimentary basins in Greenland. The bids are from the 2009 workshop on the “Assessment of the sediment-hosted copper potential in Greenland” (Stensgaard et al. 2011). The exact estimates should be used with precautions and will, besides always being a statistical derived estimate, be a reflection of confidence and how much is known and how many data that is available from an area. Estimate of undiscovered copper resources (metric tons of Cu metal) Areas Reduced Cu Revett Cu Redbed Cu Source Permian, Jameson Land Basin, East Greenland 240,000 t 568,000 t none Stensgaard