Manganese Deposits

©2009 Dr. B. C. Paul

Acknowledgement is given to the following sources, USBureau of Mines, USGS,

Locations of Major Manganese Deposits

Typical Formation Location for Sedimentary Manganese Deposits

Commercial Deposits

• Many of todays deposits have had lateritic weathering– Manganese minerals often in hard clusters– Lots of silica and clay like fines

Tonnage of Typical Sedimentary Manganese Deposits

                                                                                                                 

Median size is 7.3Million metric tonnes

Big ones can be280,000,000 metrictonnes

Typical Ore Grades

Grades tend be in the lower to mid30’s as a percent.

Pyrolusite

MnO2 S.G. 4.4 - 5.06, Average = 4.73 Hardness 6-6.5 Color Steel gray, Iron gray, Bluish gray. Fluorescence – NoneMagnetic NoManganese 63.19%

Manganite

MnO(OH) S.G. 4.3 - 4.4, Average = 4.34 Hardness 4Color Black, Gray, Grayish black. Fluorescence – NoneMagnetic NoManganese 62.47%

Hausmannite

Mn3O4 S.G. 4.7 - 4.84, Average = 4.76 Hardness 5.5Color Brownish black, Grayish. Fluorescence NoneMagnetic NoManganese 72.03%

Braunite

Mn7SiO12 S.G. 4.72 - 4.82, Average = 4.76Hardness 6-6.5 Color Grayish black, Brownish gray, Dark brownish black.Fluorescence NoneMagnetic NoManganese 63.6%

Rhodochrosite

MnCO3 S.G. 3.69 Hardness 3Color Pinkish red, Red, Rose red, Yellowish gray, Brown. Fluorescence None Magnetic No

Manganese 47.79%

Rhodenite

MnSiO3

Not an ore mineral because silicate does notBreak down well for use in other processes(a lot of manganese is used in steel makingAnd silica is bad news in steel).

Psilomelane

(Ba,H2O)2Mn5O10 S.G. 4.4 - 4.7, Average = 4.55 Hardness 5-6 Color Iron black, Dark steel gray. Fluorescence NoneMagnetic NoManganese 46.56%Barium 23.27%

Franklinite

Zn0.6Mn2+0.3Fe2+0.1Fe3+1.5Mn3+0.5O4S.G. 5.07 - 5.22, Average = 5.14 Hardness 5.5-6 Color Black, Brownish black. Fluorescence NoneMagnetic weakManganese 18.58%Zinc 16.59%Iron 37.78%

Manganese Deposits Can Also Be Volcanic Related

• Manganese rich solutions coming from vent zones on the ocean floor– These can be scooped up on to continents

Volcanic Associated Deposits are Distinctly Smaller

A single median depositMay be only47,000 metric tonnes.

A big ore body is stillUnder 1 million metricTonnes.

Grades are Higher

Lower 40’s for %.

Lastly Manganese Can Be Deposited in Veins from moving hot

fluids.

These deposits tend to beYoung and small

25,000 metric tonnes aCommon vein deposit

A big one is 260,000 metricTonnes.

Grade Tends to be Only in the 30th percent range.

SometimesCoproducts in theVeins can beImportant.

Processing

• Because a lot of deposits are Laterites– First take advantage of larger size and

hardness of the good stuff– Do some light crushing

• Then do some screening• Silica tends to be in smaller pieces

– Then try to wash away the fines

The Log Washer

Feed

Heavy – big settle

Little and Light wash away

Heavy and big pushed backUp by paddle action

Particularly trying to wash outSticky clay (clay can blindScreens)

Gravity Recovery of Fines

• Silica is light• Manganese minerals

heavy• Use things like jigs

and spirals

Lighter stuffGets whirled out toThe side as itSpins down

What is it Used for?

Manganese Uses

Construction

Machinery

Transportation

Other

Chemical

What is the Production and Reserves?

Manganese Production and Reserves

0

2000

4000

6000

8000

10000

12000

Production Reserves/50Th

ou

sa

nd

s o

f M

etr

ic T

on

ne

s Other

Ukraine

South Africa

Mexico

India

Gabon

China

Brazil

Australia

United States

What is it Worth?

Manganese Price

0

0.2

0.4

0.6

0.8

1

1.2

19

00

19

12

19

24

19

36

19

48

19

60

19

72

19

84

19

96

20

08

2009$ per Lb

Still holding around $1 in 2010