Pyhäsalmi: Cu-Zn Mining In The Heart Of Finland

Andrew Dobrzański

University of Edinburgh

Many thanks to:

Hannah Stephenson (PhD Student – Cardiff)

Cardiff SEG Student Chapter & Cardiff University

Society of Economic Geologists

SRK Consulting

First Quantum Mining - Timo Mäki & Mikko Numninen

Mining in Finland• Recorded mining since the 1500s,

•March 1910 the Outokumpu copper deposit discovered,

• 1917 Finland declares independence,

• 1924 Outokumpu Oy nationalised,

• 1958 Pyhäsalmidiscovered,

• Presently 40 active mines, 30 active projects, complete geophysical mapping,

Metal Deposits in

Finland

gtk-kauppa.fi

Formed during three main time tectonic periods:

(1) 3200–2700 Ma Archean cratons,

(2) 2500–1920 Ma volcanism, sediments and intrusive magmatism,

(3) 1930–1770 Ma Svecofennian orogen,

Tectonics of Fennoscandia

(Andersson et al. 2004, Hanski 2015)

Kola Craton

Karelian CratonLapland Greenstones

Belomorian Belt

Svencofennian Domain

Trans-scandinavian Igneous Belt

Svenco-Norwegian Domain

Oslo Rift

Caledonides

Formed during three main time tectonic periods:

(1) 3200–2700 Ma Archean cratons,

(2) 2500–1920 Ma volcanism, sediments and intrusive magmatism,

(3) 1930–1770 Ma Svecofennian orogen,

500 km

Karelia

Kola

Tectonics of Fennoscandia

(Andersson et al. 2004, Hanski 2015)

Kola Craton

Karelian CratonLapland Greenstones

Belomorian Belt

Svencofennian Domain

Trans-scandinavian Igneous Belt

Svenco-Norwegian Domain

Oslo Rift

Caledonides

Formed during three main time tectonic periods:

(1) 3200–2700 Ma Archean cratons,

(2) 2500–1920 Ma volcanism, sediments and intrusive magmatism,

(3) 1930–1770 Ma Svecofennian orogen,

Discovery

• Discovered by chance in late September 1958,

•Diamond drilling carried out October 1958,

• Open pit by 1962 in order to fund the development of the underground mine,

•Underground operations start in 1966,

•Ore grades:

0.93% Cu, 2.41% Zn, 0.4 g/t Au, 14 g/t Ag, 37.6% S

Topping-out (December 1959)

Mine DevelopmentC

arrot / P

orkkan

a

Po

tato / P

eru

na

• Not a simple mine to construct,

• ‘Carrot’ shaped ore-body,

• 1960’s shaft sunk to 400m depth,

• Mine nearing the end of production in 1996,

• In December 1996 the ‘potato’ was found by Timo Mäki extending the mine life by over 20 years,

• New shaft sunk to 1400m in 2001,

Pyhäsalmi Ore Mineralogy

5cm

Pyrite - FeS2

Sphalerite - (Zn,Fe)S

Chalcopyrite - CuFeS2

Pyrrhotite - Fe7S8

± Dolomite – CaMg(CO3)2

± Calcite - CaCO3

± Barite - BaSO4

Hosted within highly deformed and metamorphosed rhyolites,

Imaña 2003

Volcanogenic Massive Sulphide

(VMS)

• Typically VMS forms on or just below the sea floor below a carbonate/sulphate cap,

• Analogue environments are thought to be black smokers,

• Metals precipitate from cooling acidic reduced waters,

Doyle et Allen (2003)

Chalcopyrite (CuFeS2)Pyrrhotite (Fe7S8)

Pyrite (FeS2)Sphalerite (Zn,Fe)S

Barite (BaSO4 )Dolomite (CaMg(CO3)2)

Recent black smoker systemNaturhistorisches Museum Wien

Pyhäsalmi OrePyhäsalmi Mine – First Quantum

50cm50cm

Mäki et al. 2015

Mäki et al. 2015

Future of Pyhäsalmi

Pyhäsalmi has now provided income and employment since the 1960s,

The Finnish tax system benefits the local area,

85% of all money is spent from exploration to rehabilitation stays in the place the ore is mined,

Pyhäsalmi has helped to train generations of Finninsh geologists and engineers ,

But what is the future?

EMMA Cosmic Ray Experiment

LAGUNA

Large Apparatus for Grand Unification and Neutrino Astrophysics

Pyhäsalmi Power Project

1 m3 of water at the top of the mine has a potential energy of 13.7 MJ,

(144 1L kettles)

Potentially a significant power generation scheme,

Requires power (preferably renewable) to pump the water back to the surface,

P.E. (J) = m * g * h

Hydroponics

Pea shoots, Rocket, Wasabi, Red basil,

Guardian.com

Google

Google

Radish, Garlic,Chives, Fennel,

Growing Underground

Up to 60kg per day of: