Long-term projects

CNT Labs is currently working under several long-term projects. One of them is dedicated to the mineralogy of Au-Pd ores of the Skaergaard layered intrusion (Greenland). Geological drill core samples are supplied by Geological Survey of Denmark and Greenland (GEUS, Ministry of the Environment) and Skaergaard Minerals Corp. This project was begun in 2002 and is expected to continue for several more years. This will involve the research of over 50 samples from all ore horizons of the interior and marginal zones of the intrusion. So far, 11 samples has been studied by CNTlabs since 2002. As a result, over 3000 grains of precious metal mineral grains were separated and studied in detail, over 40 precious metal mineral phases determined, three new minerals characterized and approved by CNMMN, 8 publications published in international journals.

The Skaergaard intrusion is a main resource of PGE and Au ores in Europe. The 55Ma old Skaergaard intrusion in SE Greenland hosts a perfectly concordant, syn-magmatic, 1.8 billion ton, low grade, PGE and Au mineralisation in ilmenite-rich gabbros. The mineralisation consists of 5 main levels of Pd-concentration with Au-enrichment in the top Pd-levels. Primary magmatic, high T, characteristics are preserved. PGMs and Au minerals occur mainly in or adjacent to immiscible Cu-Fe-droplets in rims of silicate or oxide minerals and in or related to intercumulus sulphide aggregates. The bulk sulphide content in the mineralisation is c. 0.05 vol. %. More than 40 precious metal (PGE and Au- and Ag) mineral phases are recorded in the result of studies of about 3000 grains of these minerals in HS heavy mineral concentrates of 11 representative ore samples. These samples were selected from different levels of Pd- and Au-concentration in the interior and marginal parts of intrusion by the Geological Survey of Denmark and Greenland and Skaergaard Mineral Corporation and submitted to CNTlabs for processing and investigation.

List of ore minerals determined in Skaergaard intrusion

(based on investigation of about 3000 grains from HS heavy concentrates of 11 representative samples given by Geological Survey of Denmark and Greenland and Skaergaard Minerals Corp.)

Base metals sulphides
  1. bornite Cu5FeS4
  2. chalcosite Cu2S
  3. digenite Cu9S5
  4. chalcopyrite CuFeS2
  5. pentlandite (Ni,Co,Fe)9S8
  6. cobalt pentlandite (Co,Ni,Fe)9S8
  7. carrolite Cu(Co,Fe,Ni)3S4
  8. pyrrhotite Fe1-xS
  9. arsenopyrite FeAsS
  10. sphalerite (Zn,Fe)S
  11. galena PbS
  12. tetrahedrite (Cu,Fe)12Sb4S13
  13. melonite (Ni,Pd)Te2
  14. orcelite Ni5-xS2
  15. unnamed (Cu,Fe)9Te2S3
  16. unnamed (Cu,Fe)6TeS2

Pd minerals
  1. skaergaardite* (Pd,Au,Pt)(Cu,Fe,Zn,Sn,Te,Pb)
  2. nielsenite** (Pd,Pt,Au)Cu3
  3. zvyagintsevite Pd3(Pb,Sn)
  4. arsenopalladinite Pd8As3
  5. guanglinite Pd3As
  6. palladoarsenide Pd2As
  7. vysotskite (Pd,Ni)S
  8. vasilite (Pd,Cu,Fe)16S7
  9. braggite (Pt,Pd,Ni)S
  10. keithconnite Pd3±x(Te,Sn,Pb)
  11. atokite Pd3(Sn,Pb)
  12. kotulskite PdTe
  13. merenskyite PdTe2
  14. isomertieite Pd11Sb2As2
  15. naldrettite* Pd2(Sb,Sn)
  16. froodite PdBi2
  17. cabriite Pd2CuSn
  18. telargpalite (Pd,Ag)3Te
  19. (Pd,Cu,Au)-alloy
  20. (Pd,Cu,Sn)-alloy
  21. (Cu,Pd)-alloy
  22. unnamed (Pd,Au)3Cu
  23. unnamed Pd3(Cu,Fe)6Te2S3
  24. unnamed(Pd,Ag)2Te
  25. Pd3Ag2S

Au minerals
  1. tetraauricupride (Au,Pd)Cu
  2. auricupride Cu3Au
  3. unnamed Au3Cu
  4. (Au,Cu,Pd)-alloy
  5. (Au,Cu,Pd,Ag)-alloy
  6. (Cu,Au,Pd)-alloy
  7. (Au,Ag)-alloy
  8. unnamed Cu2AuPd
  9. unnamed Au2CuPd
  10. unnamed Au3Ag

Bold — dominant minerals in the central part of the intrusion; bold italic — dominant minerals in the margin part of the intrusion; *-red — new minerals approved by CNMMN and have published (Rudashevsky, et al., 2004; Cabri et al., 2005); **-red — mineral approved by CNMMN and submitted for publication (McDonald et al., 2005 in press)

Sulphide globules with inclusions of PdCu
(Skaergaardite — new mineral, approved in 2004)
preserved after disintegration of the sample 90-24, 1057 (1-95);
polished section, SEM-image (BIE).