Salient features and physical characteristics of granite rocks of Bangladesh


Salient Features of Maddhapara Hardrock Mine:

1.

Location of the mine

:

Maddhapara, Dinajpur, Bangladesh.
2.
Depth of rock
:
124 meter from the surface.
3.
Reserve and mine area
:
Reserve in the mine area of 1.0 km × 1.2 km =1.2 km2 
is 174 million tons
4.
Point load strength
:
24,000 psi
5.
Annual Production
:
1.65 million tons.
6.
Life of the mine
:
Analysis based on 41 years (including development period) but mine operation life may be extended for more than 70 years.
7.
Employment opportunity
:
Direct -766, Indirect – 10,000.
8.
Method of mine
:
Room and Pillar/ Sub-Level Drift Stopping Method.
9.
Mode of Entry
(Length and dia. of shafts)
:
Two Vertical shafts (The length of the skip shaft is 380m and cage shaft 330 m. Inner dia of both shafts is 5.0 m. and distance between two shafts is 85 m).


Main fans for inside air circulation in the tunnel
Physico-chemical analysis of representative samples of hard rocks collected from  Mining site indicates alternative uses as more worthy constructional materials. Chemical analyses of the hard rock being carried out are found as follows (average of several samples):

Silica                                                                                                  53-60%,
Alumina                                                                                              15-20%,
Iron oxide                                                                                             6-10%,
Calcium oxide                                                                                             6-10%,
Magnesium oxide                                                                                        4- 6%,
Titanium oxide                                                                                          0.7-1.0%,
Sodium oxide                                                                                             1.5-2.8%,
Potassium oxide                                                                                2.4-3.0%,
Manganese oxide and                                                                        0.1-0.2%
traces of other metal oxides.


The mineral though rich in alumina, its major constituent is silica that has been identified as Granodiorite and Micro-granodiorite deposit. The rock exhibits grey to greyish black colour, depending on its weathering level. Due to weathering, feldspar was decomposed and dark minerals lost their crystalline forms. Upon finely grinding the powder exhibits a very good pozzolanic characteristic.

 
Location: Bangladesh

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