Danmarks og Grønlands Geologiske Undersøgelse har tidligere undertaget prøver af tungmineralkoncentrater i Grønland. Nedenunder er disse prøvemetoder beskrevet efter år. Desværre findes der ikke beskrivelser af alle årgangene, da nogle indsamlings kampagner var af mere lokal karakter og været knyttet til andre projekter og derfor ikke findes i særskilte rapporter. Hvilket betyder at metadata omkring prøverne ikke findes. I alt findes analyser af 725 entydige tungmineral koncentrat prøver. De 319 nævnte prøver nedenunder omfatter ikke alle tungmineral koncentraterne, som er indsamlede de nævnte år. Prøver taget udenfor kampagnerne forekommer i den samlede liste. Brug af dataene skal vises med omhu, kvalitet bør kontrolleres med andre data.

Årene 1982-1986

En regional prøveindsamling var lanceret mellem 1982 og 1986, prøverne er beskrevet i Appel 1989. Disse prøver har fået analyse batch numrene 10, 36 og 55. Numrene 10 og 36 er analyseret hos Activation Laboratories og nummer 55 hos Bondar-Clegg and Co. Ltd., begge to i Canada. 210 prøver var indsamlet og alle foretaget i Nuuk området.

Prøvetagnings procedure: I felten: De kystnære områder var tilgået med båd, mens indlandet blev tilgået med helikopter. Fire liter af grus og sand var indsamlet og siet gennem en 6 masket bronze si. Det fine materiale (ca. 10 %) blev vasket og scheelite mineraler optalte under ultraviolet lampe. I laboratoriet: Prøven blev tørret og separeret af bromoform, den tunge del vejet of scheelite minerlerne igen optalte. En lille prøvesplitter separerede 0,5 g til analyse for elementerne W, Mo, Pb, Cu, Cr, Co, V, Mn, Zr, Ni og Fe. Over årene er prøve kampagnerne såvel som analysemetoderne ændret. 1983 var de fire liter øget til fem. I 1985 steg materialet til 5-6 litrer (eller 10 kg). I 1986 var en plastik si med 1 mm huller fyldt tre gange (5-8 kg) til hver prøve og volumen af finfraktionen opmålt . Omkring 10 g af hver prøve var analyseret af Bondar-Clegg for elementerne (Sc, Cr, Fe, Co, Ni, As, Se, Rb, Mo, Ag, Cd, Sb, CS, BA, La, Eu, Tb, Yb, Hf, Ta, W, Ir, Au, Th og U). Bemærke at analyserne under målegrænsen gives som ?0? (nul) og ikke målte værdier som ?-1? (minus én) for disse prøver, indsamlet under omtalte kampagner (i årene 1982-1986, dvs. analyse batch numre 10, 35 og 55).

År 1991

I 1991 var 106 elve prøvetaget for tungmineral koncentrater, i den sydlige del af Nuuk området, mellem 62°30?N og 64°N. Prøve proceduren var: 5-10 liter af sediment, < 5 cm, var indsamlet fra 2-5 sub-lokaliteter i elven. Våd sien af materialet opdelte prøven i mindre-en og større-end 0,5 mm, hvor den grove den var inspiceret for økonomiske mineraler. Fin fraktionen var separeret til tungmineral koncentration vha. en roterende vaskepande instrument "goldhound" (se Erfurth et al., 1992 for reference). Tung mineral koncentratet blev afskibet til Danmark og tørret og splittet til analyse. Analyserne var foretaget af Activation Laboratories, Canada, som målte 35 grundstoffer, herunder guld med INAA og ICP-ES. Analyse batch numrene er 10 og 36. Disse to batch numre giver 103 entydige prøver. Derudover indeholder analyse batch nummer 41, grundstofferne Pb, Cu, Ni og Zn.

År 2004

Analyse batch numrene 1093 og 194 er beskrevet i GEUS rapport nr. 2004/42 og var indsamlet i Qaanaq regionen i NordvestGrønland i 2003. Seks prøver var indsamlet i denne feltsæson via sivning af 1,0 mm materiale på lokaliteten og en præ-koncentrat produceret med vaskepande af finfraktionen. I København var mineraler med densitet over 2,8 g/cm3 separeret med tungvæske.

Resten

De resterende 406 prøver (analyse batch numre: 10, 15, 21, 35, 36, 41, 55, 165, 166, 193, 194, 374, 375, 376, 1014, 1015, 1016, 1017, 1029, 1030, 1051, 1052, 1077 og 1078) er udover de tidligere nævnte laboratorier analyseret på Risø Nationale Laboratorie i Danmark. Da rapporter ikke har været tilgængelige til beskrivelsen af disse prøver er beskrivelsen begrænset til analyserne. Sandsynligvis er lignende procedurer er gentaget for disse prøver, som ovenover. Indlæsningen af målegrænserne og ikke målte værdier har ikke været konsistent, men kan være "0" eller også negative værdier og ikke målte værdier kan enten være "0" eller også tomme felter.

Referencer:

Appel, P.W.U., 1989. Investigations of heavy mineral concentrates from stream sediment samples collected during the period 1982 to 1986 in the Nuuk area, West Greenland. GGU Open File Report 89/1. 17 pp., 10 tables, 35 plates. 370 DKK (GRF no. 20324)

Erfurt, P., Appel, P.W.U. & Lind, M., 1992. Geochemical investigation of heavy mineral concentrates from stream sediments in southern West Greenland, 62°30´N to 64°00´N - 1991 results. GGU Open File Report 92/1. 39 pp., 13 figs, 3 tables. 50 DKK

Thomassen, B. & Krebs, J.D., 2004. Mineral exploration of selected targets in the Qaanaaq region, North-West Greenland: follow-up on Qaanaaq 2001. Danmarks og Grønlands Geologiske Undersøgelse Rapport 2004/42. 38 pp. + tables. 238 DKK

The Geological Survey of Denmark and Greenland has previously conducted sampling campaigns of heavy mineral concentrate in Greenland. The sampling methods are described according to their sampling years below. Unfortunately, not all the samples have reported as the campaigns in have not been undertaken on regional scale and therefore fallen under smaller projects or sampled under projects that have had other objects, and not all elements were considered relevant in the reports, translating to that metadata concerning the analyses are missing. All together there are geochemical analyses of 725 heavy mineral concentrate samples. The samples that are mentioned in reports below, are 319 in number, and do not comprise all heavy minerals samples collected the specified years. Samples collected in un-mentioned campaigns do occur in the full list. Use of data that is not mentioned here, needs caution and the quality should be weighed against other data.

Years 1982-1986

A regional sampling campaign was conducted between 1982 and 1986, these samples are described in Appel 1989. These samples comprise the analysis batch numbers 10, 36 and 55. Numbers 10, 36 are analysed at Activation Laboratories and 55 analysed at Bondar-Clegg and Co. Ltd., both in Canada. In this campaign 210 samples were collected and are all sampled in the area around Nuuk.

Sampling procedure: In the field: The coastal areas were accessed by boat while inland areas were accessed by helicopter. Four litres of coarse gravel and sand were collected and sieved through a 6 mesh of brass. The fines (c. 10 %) was panned and inspected in ultraviolet light and the scheelite grains counted. In the laboratory: The samples were dried and separated by bromoform, the heavy material was weighed and the scheelite grains counted again. A small splitter separated c. 0.5 gram of each sample for analysis of W, Mo, Pb, Cu, Cr, Co, V, Mn, Zr, Ni and Fe. During the years the sampling programme as well as the analysis methods changed. In 1983 the four litres were added up to five. In 1985 the material increased to 5-6 litres (or 10 kg). In 1986 a plastic sieve with 1 mm holes used and filled three times (5-8 kg) for each sample, the volume of fines was measured. C. 10 gram of each sample was analysed by Bondar-Clegg for (Sc, Cr, Fe, Co, Ni, As, Se, Rb, Mo, Ag, Cd, Sb, CS, BA, La, Eu, Tb, Yb, Hf, Ta, W, Ir, Au, Th and U) analyses. The reader should note that the analyses below detection limit is given as "0" (zero) and not analysed as "-1" for the samples collected in this campaign (year 1982-1986, i.e. batch numbers 10, 35 and 55).

Year 1991

In 1991, 106 streams were sampled for heavy mineral concentrate, in the southern part of the Nuuk area, between 62°30?N and 64°N. Sample procedure was as follows: 5-10 litres of detrital material, < 5 cm, were collected, from 2-5 sub-localities in the stream bed. Wet sieving split the sample in less-than and bigger-than 0.5 mm, and the coarser fraction inspected for economic minerals. The fine fraction was heavy minerals concentrate was produced using a rotary panning device "goldhound" (see Erfurt et al., 1992 for reference). The heavy mineral concentrate was shipped to Denmark and dried and further spilt for analytical purposes. Activation Laboratories, Canada, analysed the samples for 35 elements including gold, with INAA and ICP-ES. Analyses batches are numbered 10 and 36. Unique samples number 103 for these two batches. In additional batch 41, has analysed Pb, Cu, Ni and Zn.

Year 2004

The analyses batch no. 193 and 194 have been described in GEUS report 2004/42, and were sampled in 2003 in the Qaanaaq region in North-West Greenland. Six samples were collected in this campaign and sieving of 1.0 mm material on site and a pre-concentrate by panning of the fine fraction. In Copenhagen minerals with > 2.8 g/cm3 density was produced by heavy liquid separation.

The rest

The remaining 406 samples (analyses batch numbers: 10, 15, 21, 35, 36, 41, 55, 165, 166, 193, 194, 374, 375, 376, 1014, 1015, 1016, 1017, 1029, 1030, 1051, 1052, 1077 and 1078) have been analysed in addition to the laboratories mentioned above, at Risø National Laboratory in Denmark. As reports have not been available for writing up these analyses, the description is limited to the analyses. Chances are, however, that sampling procedures are similar to the descriptions above. The analyses below detection limits of the remaining 406 unique samples have not been consistent, but are presented as "0" or as negative values and elements that have not been measured as "0" or empty cells.

References:

Appel, P.W.U., 1989. Investigations of heavy mineral concentrates from stream sediment samples collected during the period 1982 to 1986 in the Nuuk area, West Greenland. GGU Open File Report 89/1. 17 pp., 10 tables, 35 plates. 370 DKK (GRF no. 20324)

Erfurt, P., Appel, P.W.U. & Lind, M., 1992. Geochemical investigation of heavy mineral concentrates from stream sediments in southern West Greenland, 62°30´N to 64°00´N - 1991 results. GGU Open File Report 92/1. 39 pp., 13 figs, 3 tables. 50 DKK

Thomassen, B. & Krebs, J.D., 2004. Mineral exploration of selected targets in the Qaanaaq region, North-West Greenland: follow-up on Qaanaaq 2001. Danmarks og Grønlands Geologiske Undersøgelse Rapport 2004/42. 38 pp. + tables. 238 DKK