Carbonatites

PGE, noble metal and sulphide mineralization in phoscorites and carbonatites of Kovdor (Kola peninsula, Russia) and Phalaborwa (South Africa) massifs

N.S. Rudashevsky, Yu.L. Kretser and V.N. Rudashevsky

PGE and PGM of the sulphide flotation concentrate from carbonatites of Kovdor massif

(ppm): Pt 0.22, Pd 0.22 Rh 0.04, Ru 0.005, Au 0.06;

Total 0.48 ppm of PGE


Noble metal minerals from heavy mineral concentrates:
  1. ISOFERROPLATINUM Pt3Fe — 5 grains
  2. COOPERITE (Pt,Ni)S – 2 grains
  3. BRAGGIE (Pt,Ni,Pd)S*
  4. SPERRYLITE PtAs2 – 2 grains
  5. MONCHEITE Pt(Te,Bi)2 – 3 grains
  6. RUSTENBURGITE (Pt,Pd)3Sn*
  7. MERTIEITE I (Pd,Pt)11(Sb,As,Sn)4 and
  8. MERTIEITE II (Pd,Pt)8(Sb,As,Sn)3 – 8 grains
  9. ATOKITE (Pd,Pt)3(Sn,Sb) – (in 2 grains)
  10. ISOMERTIEITE (Pd,Pt)11As2(Sb,Sn,Te)2*
  11. SOBOLEVSKITE (Pd,Pt)(Bi,Te)*
  12. ARSENOPALLADINITE (Pd,Pt)8(As,Te,Sn,Sb,Bi,Pb)3*
  13. ZVYAGINTSEVITE (Pd,Pt)3(Pb,Bi,As,Te,Sb) – 2 grains
  14. PLUMBOPALLADINITE Pd3(Pb,Bi)2 – 1 grain
  15. UNNAMED PHASE (Pd,Ag)2(Te,Pb,Sb,Sn)*
  16. NATIVE GOLD (Au,Ag) – 6 grains,
  17. ELECTRUM AuAg – 2 grains
  18. HESSITE Ag2Te*
  19. ARGENTOPENTLANDITE Ag (Fe,Ni)8S8*
* inclusion in one grain

 

Grain sizes of precious metal minerals - 30-100 µm

PGMs of carbonatites of Kovdor massif (1-12); SEM image (BIE)

IFP — isoferroplatinum, COOP — cooperite, SP — sperrylite, MNCH — moncheite, MRT I — mertieite I , MRT II — mertieite II, AT — atokite, ISM — isomertieite, APD — arsenopalladinite, RST — rustenburgite, BR — braggite, ZV — zvyagintsevite, SOB — sobolevskite, (Pd,Ag)2(Te,Pb) — unnamed mineral, PO — pyrrhotite, CP — chalcopyrite, GN — galena, MT — magnetite.



 

Gold and silver minerals of carbonatites of Kovdor massif (1-5); SEM image (BIE).

AuAg — electrum, (Au,Ag) — native gold, AGPN — argentopentlandite, HS — hessite, CP — chalcopyrite, PO — pyrrhotite, PN — pentlandite, GN — galena, SOD — sodalite.



 

Ore forming sulphides in carbonatites of Kovdor massif (1-5); SEM images (BIE).

PO — pyrrhotites, CP — chalcopyrite, PN — pentlandite, SPH — sphalerite, GN — galena, CT — calcite, NTR — natrolite, CNC — cancrinite.



 

Some PGE and Au of the sulphide flotation product from carbonatites of the Loolecop deposit

(ppm): Pt 0.23 Pd 0.40 Au 2.00;

Total 0.63 ppm of PGE

Noble metal minerals of heavy mineral concentrates from the sulphide flotation product

N Mineral Formula Number of grains Grain size (Deff.ìm)
min max average
1SperrylitePtAs221167738
2Cabriite(Pd,Pt)2Cu(Sn,Sb)4344135
3MajakitePdNiAs2195336
4Taimyrite(Pd,Cu,Pt)3Sn1--35
5Atokite(Pd,Pt,Cu)3(Sn,Bi,Pb)1--23
6Mertieite II(Pd,Cu)8(Sb,Sn)31--29
7Arsenopalladinite(Pd,Pt,Cu)8(As,Sn,Bi)31--26
8Unnamed phasePd11As2(Pb,Hg)21>--39
9FrooditePdBi22(incl.)264
10Electrum*AuAg73010655
11Tetra-auricuprideAuCu5219161
12GoldAu3Ag2(incl.)2148
13KusteliteAg3Au121612449
14Silver**Ag24712155
15StromeyeriteAg1-xCu1+xS>10(incl.)329-
16JalpaiteCu(Ag,Fe)3S21(incl.)--23
17Hessite*Ag2Te1--14
18Argentopentlandite**Ag(Fe,Ni)8S82121915
* determined in the heavy concentrate of carbonatite ores;
** determined in polished sections of carbonatites; incl. — inclusion.



 


PGM grains from heavy concentrates of sulphide product of the Loolecop deposit (1-12); SEM image (BIE).

SP — sperrylite, CBR — cabriite, TMR — taimyrite, ATK — atokite, MJK — majakite, APD — arsenopalladinite, MRT II — mertieite II, FR — froodite, Pd11As2(Pb,Hg)2 — unnamed phase, (Ag,Au) — kustelite, BORN — bornite, CP — chalcopyrite.



 


Grains of gold and silver minerals from heavy concentrate of sulphide flotation product of the Loolecop deposit (1-11); SEM images (BIE).

AuCu — tetra-auricupride; AuAg — electrum; Ag3Au — kustelite; (Ag,Au), Ag — native silver; JLP — jalpaite; STRM — stromeyerite; BORN — bornite; CP —chalcopyrite; DGN — digenite; COPN — cobalt pentlandite; Bi — native bismuth.



 


Ore forming sulphides and native metals from carbonatites of Loolecop deposit (1-14); SEM images (BIE).

1 — polished section of the ore, 2-10 — grains from heavy concentrates; BORN — bornite, CP — chalcopyrite, DGN — digenite, ANL — anilite, DJR — djarleite, CHLC — chalcosine, PRK — parkerite, GN — galena, MIL — millerite, WITT — wittichenite, SHD — shadlunite, Bi — native bismuth, Ag — native silver, Cu — native cupper, BRS — brass, Pb — native lead, CT — calcite, MT — magnetite, ThO2 — thorianite, MNZ — monazite.



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