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 7.3 Million metric tonnes Big ones can be 280,000,000 metric tonnes

Typical Ore Grades Grades tend be in the lower to mid 30’s as a percent.

Pyrolusite MnO 2 S.G , Average = 4.73 Hardness Color Steel gray, Iron gray, Bluish gray. Fluorescence – None Magnetic No Manganese 63.19%

Manganite MnO(OH) S.G , Average = 4.34 Hardness 4 Color Black, Gray, Grayish black. Fluorescence – None Magnetic No Manganese 62.47%

Hausmannite Mn 3 O 4 S.G , Average = 4.76 Hardness 5.5 Color Brownish black, Grayish. Fluorescence None Magnetic No Manganese 72.03%

Braunite Mn 7 SiO 12 S.G , Average = 4.76 Hardness Color Grayish black, Brownish gray, Dark brownish black. Fluorescence None Magnetic No Manganese 63.6%

Rhodochrosite MnCO 3 S.G Hardness 3 Color Pinkish red, Red, Rose red, Yellowish gray, Brown. Fluorescence None Magnetic No Manganese 47.79%

Rhodenite MnSiO 3 Not an ore mineral because silicate does not Break down well for use in other processes (a lot of manganese is used in steel making And silica is bad news in steel).

Psilomelane (Ba,H 2 O) 2 Mn 5 O 10 S.G , Average = 4.55 Hardness 5-6 Color Iron black, Dark steel gray. Fluorescence None Magnetic No Manganese 46.56% Barium 23.27%

Franklinite Zn0.6Mn2+0.3Fe2+0.1Fe3+1.5Mn3+0.5O4 S.G , Average = 5.14 Hardness Color Black, Brownish black. Fluorescence None Magnetic weak Manganese 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 deposit May be only 47,000 metric tonnes. A big ore body is still Under 1 million metric Tonnes.

Grades are Higher Lower 40’s for %.

Lastly Manganese Can Be Deposited in Veins from moving hot fluids. These deposits tend to be Young and small 25,000 metric tonnes a Common vein deposit A big one is 260,000 metric Tonnes.

Grade Tends to be Only in the 30 th percent range. Sometimes Coproducts in the Veins can be Important.

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 back Up by paddle action Particularly trying to wash out Sticky clay (clay can blind Screens)

Gravity Recovery of Fines Silica is light Manganese minerals heavy Use things like jigs and spirals Lighter stuff Gets whirled out to The side as it Spins down

What is it Used for?

What is the Production and Reserves?

What is it Worth? Still holding around $1 in 2010