PGM-Au bearing low-sulfide ores of layered intrusions and tailings

Two types of PGE-bearing sulphide ores in Yoko-Doviren layered massif,
Northern Pribaykalie, Russia

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


PGE mineralization of sulphide ores in anorthosites from Yoko-Doviren massif

SiO2 44.5 TiO2 0.1 Al2O3 28.9 Fe2O3 2.4 FeO 3.3 MgO 2.0 CaO 14.1

Na2O 1.7 K2O 0.20 H2O+ 1.8
Ni 0.20 Cu 0.40 S 0.91
(ppm) Pt 1.56 Pd 3.2 Rh 0.04 Ru 0.01 Ir 0.09 Os 0.01 Au 1.44 Total PGM 5


PGMs of the heavy concentrates

N Mineral Formula Number of grains Grain size, mm Vol.% of mineral
min max avg
1Moncheite**(Pt,Pd)(Te,Bi,Pb)2228613440
2Tetraferroplatinum**(Pt,Pd)(Fe,Cu,Ni)154422413
3PotaritePdHg174622923
4Gold(Au,Ag) 7 29 53 38 14
5ElectrumAuAg
6Silver(Ag,Au)
7Kotulskite**Pd(Te,Pb,Bi)43747417
8Paolovite**(Pd,Pt)2Sn2*624151
9SperrylitePtAs21*101311 2
10Atokite(Pd,Au)3(Sn,As,Sb)1*72513
11MajakitePdNiAs1*286
12IsoferroplatinumPt3+x(Fe,Cu,Ni)1*92114
13Zvyagintsevite(Pd,Pt)3Pb1*10>1211
14Mertieite I (?)(Pd,Pt)8(Sb,Te)31*243
15Telargpalite (?)(Pd,Ag)3(Te,Pb)1*132
16Sobolevskite**Pd(Bi,Te)2132
17Unnamed(Pd,Cu,Fe,Hg)3STe1*182019
18StephaniteAg5SbS41295339
19ArgentiteAg2S1263831
20Amalgam(Ag,Hg)1202020
 Total 73   100
* Does not form independent grains;
**also determined in the polished sections of ores.

 

Grains of precious metal minerals from heavy concentrates of low sulphide type ores (1-20); SEM images (BIE).

Grains of precious metal minerals from heavy concentrates of low sulphide type ores (1-20); SEM images (BIE).

MNCH — moncheite, TFP — tetraferroplatinum, IFP — isoferroplatinum, PdHg — potarite, KT — kotulskite, SP- sperrylite, AT — atokite, PLV — paolovite, MK — majakite, ZV — zvyagintsevite, MRT — mertierite I, TP —telargpalite, UN — unnamed (Pd,Cu)3TeS, CUB — cubanite, CP — chalcopyrite, TR — troilite, PN — pentlandite, PL — plagioclase, MT — magnetite, CHL — chlorite, EP — epidote.


 

Mass balance of PGE in disseminated low sulphide ores of
Yoko-Doviren massif

Measured:Pd 3.2 ppm, Pt 1.56 ppm — in ores; 360 ppm — Pd in pentlandite;
Calculated: 0.7 % — amount of pentlandite in ores; 3.2-(0.7x320)=2.52 ppm of Pd dissolved in pentlandite; 3.2-2.52 = 0.68 ppm — amount of Pd in PGMs

For reported whole-rock PGE concentrations Pd/Pt (in PGMs) = 0.68/1.56 = 0.44


Distribution of Pd in PGMs

Mineral % of Pd in the mineral % of the mineral from sum PGE % of Pd within the mineral in ore
Potarite 35 27 9.45
Kotulskite 45 8 3.7
Others 50 3 1.5
Total Pd in PGM 14.65

Distribution of Pt in PGMs

Mineral % of Pd in the mineral % of the mineral from sum PGE % of Pd within the mineral in ore
Moncheite 41 47 19.27
Tetraferroplatinum 76 15 11.40
Total Pt in PGM 30.67

For calculated from PGM distributions Pd/Pt (in PGMs) = 14.65/30.67 = 0.48


 

PGE mineralization of investigated sample of -u-Ni
sulphide rich ores from Yoko-Doviren massif

(wt. %) Ni 2.14 Cu 0.42 Co 0.104 S 19.8 Zn 0.029 Pb 0.011
(ppm) Pt 0.112 Pd 0.725 Rh <0.02 Ru 0.027
Ir 0.018 Os 0.012 Au 0.44 Total 0.9 ppm of PGE


General characteristics of PGE-bearing phases, and Au and Ag minerals from the heavy concentrate

N Mineral Formula Number of grains Grain size, mm Vol.% of the mineral
min max avg
1Sperrylite*PtAs2519633789.5
2GeversitePtSb21--190.4
3Sudburyite*(Pd,Ni)(Sb,Bi)51556316.9
4Mertieite IPd8Sb31--140.2
5UnnamedPd2Sb1--482.7
6Kustelite (?)(Ag,Au)1--150.3
-Total 60   100
7Maucherite*(Ni,Co,Fe)11As833**197637 
* also determined in polished sections
**grain sizes of maucherite for 33 grains from heavy concentrate

 

Grains of PGE and Au minerals from  heavy concentrate of rich Cu-Ni sulphide ores (1-10); SEM image (BIE).

Grains of PGE and Au minerals from heavy concentrate of rich Cu-Ni sulphide ores (1-10); SEM image (BIE).

SP — sperrylite, GV — geversite, SDB — sudburyite, MRT — mertieite I, Pd2Sb — unknown phase, MCH — maucherite, (Ag,Au) — kustelite, PO — pyrrhotite, CP — chalcopyrite, GN — galena, ACT — actinolite, CHL — chlorite.


 

PGE and Au minerals’ relative contents of heavy concentrates (a, b)


Grain sizes of PGMs (a, b)

CNT MC Inc.