A presentation On

Heavy Minerals

submitted by……………… shuvo das Id No : 14207101

Institute of marine science and fisheries ; University of chittagong

MineralA mineral is a naturally occurring solid chemical

substance formed through bio- geochemical processes, heaving characteristics chemical composition, highly ordered atomic structure and specific physical properties.

A mineral is an element or a chemical compound that is normally crystalline and that has been formed as a result of geological processes.

Heavy MineralsHeavy minerals have density of > 2.8gcm-3 and

typically comprise less than 1% of a sandstone. They

are more provenance specific than the light mineral

fraction .Mineral sands contain suites of minerals with high

specific gravity known as heavy minerals.

Furthermore, a distinction is made in the references

according to the density of the useable

heavy minerals:

• the heavy heavy minerals with a density of 6.8-21 g/cm3

(mainly gold, platinum, cassiterite),

• the light heavy minerals with a density of 4.2-6.7 g/cm3

(mainly ilmenite, rutile, zircon,

monazite, magnetite, chromite),

• gemstones with a density of 2.9-4.1 g/cm3 (mainly

diamond).

Different types of mineralsMinerals are natural compounds formed through

geological process.

Minerals are needed by the body in small amounts to

help its function properly and strong.There are two types of minerals : Macro MineralTrace Mineral

Macro MineralMacro means “large” in Greek are dietary minerals

needed by the human body in high quantities. The

macro mineral group is made of calcium, phosphorus,

magnesium, sodium, potassium, chloride, sulfur.

Micro/Trace MineralTrace elements are micronutrients that are chemical

elements. A trace of something means that there is only a little of it. So even though our body needs mineral each day in small amounts for good health. Trace minerals include iron, manganese, copper, iodine, zinc, fluoride and selenium.

Heavy Mineral Extraction

Mining is the process of extracting valuable minerals

or other geological minerals form the earth crust.

Mining in broad sense means extracting of non-

renewable resources water petroleum and natural gas.

Mineral sands mining involves both dry mining and

wet (dredge) mining operation.

Heavy Mineral ExtractionThe proper extraction processes for heavy minerals depend on

the depth of the groundwaterlevel, the degree of consolidation of the sediment and its

particle size. If the groundwater level issufficiently high and the sediment finely grained, extraction is

mostly economic if large-scale cutterwheels or cutter head suction dredges that mechanically break

up solidified horizons are used. Inthe case of very high extraction banks, the ore sand can be

pushed towards the suction dredger shipusing bulldozers. When gravel and stones are involved (e.g. gold

extraction in Alaska, cassiteriteextraction in South East Asia) floating bucket wheel dredges

are used. If the groundwater level isvery low, scraper bulldozers are used.

Dry Mining Process

Dry mining typically involving the extraction of heavy

mineral ore from relatively shallow, unconsolidated,

and free flowing deposits. Dry mining is suitable

where deposits are shallow, contain hard brands of

rock or in a series of unconnected ore bodies.

Wet Mining ProcessDredge or wet mining is the best suited to ore

reservoir below the water table. Dredge mine is

artificial ponds, pumping ore in slurry form to a

floating concentrator. The ore is washed through

spirals that use specific gravity to separate the heavy

minerals sands from the lighter quartz and clay.

Transportation Deposition Of Heavy Minerals

The heavy mineral became concentration into a thin layer, composed of nearly 100% heavy mineral, is known as heavy infra layer.

Lying beneath a thin surgical layer of low density sediment is known as light supra layer.

Heavy mineral transported on the upper surface of the heavy infra layer only when the local and temporary erosion of light supra layer caused by large clasts, clast jems or downstream moving dune like bed forms exposed the heavy infra layer.

History of HEAVY MINERALS In Bangladesh

Investigation of radioactive minerals like MONAZITE by the erstwhile Geological Survey of Pakistan around the cox’s bazaar sea beach area started in 1961 and a number of precious heavy minerals were identified the same year.

After systematic surveys during 1967 to 1969 it was recognized that a potential zone of heavy mineral exists along the entire coastal belt, mainly from cox’s bazaar to badarmokam, and some areas of maheskhali, kutubdia, and matabari island.

Later in 1975 a pilot plan was installed at katali, cox’s bazaar with the cooperation of the Australian Government.By 1985 the nearly 550 km-long coastline of was surveyed either partially or completely to map the beach sand heavy minerals.It was found that the reserves were concentrated mainly along the sea beaches of chittagong & cox’s bazaar districts .

Present situation of HEAVY MINERALS in Bangladesh

Untill now 17th placer deposits are found ; 15th are in the cox’s bazaar, ctg. Sea beaches and nearby offshore islands.

In fact seven are from cox’s bazaar – teknaf sea beaches.

seven form Maheskhali Island, one each from Matarbari, Kutubdia, Nijhum Island and Kuakata.

All the seventeen deposits include 20.5 million tons of raw sand, which contains 4.4 millions of heavy minerals.

Only eight types of economically important heavy

minerals, Namely

●Ilmenite , Magnetite, Zircon, Rutile, Garnet, ● ● ● ● ●

Leucoxene, kyanite and monazite occur in these ● ●

deposits .

The total stock of these eight types of heavy minerals

these seventeen deposits is 1761000 tons.

submitted by : shuvo dasid no : 14207101Email: shuvo.das.imsf@gmail.com

Thanks to everyone