Sulphur removal by heating of pyrite ore in presence of air is called its

The following information is provided for an ore deposit:
Number of waste blocks = 10
Number of ore blocks = 5
Volume of each waste block, m³ = 600
Total cost of waste handling per m³ = Rs. 100
Tonnage of each ore block = 400
Total cost of ore handling per ton = Rs. 150
Sale price of ore per ton = Rs. 500
The net cash flow of mining the deposit in lakhs of rupees, is

A

3.4

B

2.5

C

1.0

D

0.8

Which of the following statements are true with respect to iron ore?
I. Limestone and coal are important for smelting iron ore
II. More than 20% of the world iron ore deposits are in India
III. Odisha and Jharkhand top in the production of iron ore
IV. Iran is the largest buyer of Indian iron ore

A

I, II and III

B

II and III

C

III and IV

D

II, III and IV

The bypass factor (B.P.F.) in case of sensible heating of air is (Where td₁ = Dry bulb temperature of air entering the heating coil, td₂ = Dry bulb temperature of air leaving the heating coil and td₃ = Dry bulb temperature of heating coil)

A

$$\frac{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}$$

B

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}$$

C

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}{{{\text{t}}{{\text{d}}_2} - {\text{t}}{{\text{d}}_3}}}$$

D

$$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}$$

An ore block of length 30m and height 20m having an average width of 1.5m with sharp boundary walls is mined with a minimum mining width of 2m. If the tonnage factors are 3 t/m³ for ore, 2 t/m³ for wall rock and average grade of ore is 10%, the diluted grade of ore mined in percent is

A

7.5

B

7.84

C

8.18

D

8.52

The stoping method selected, where ore body is thick veins type ore and walls are strong and steeply dipping ore i.e. footwall steeper than angle of repose of broken ore is . . . . . . . .

A

Open stoping

B

Shrinkage stoping

C

Cut and fill

D

Sub level stoping

The sensible heat factor during the heating and humidification process is given by (where h₁ = Enthalpy of air entering the heating coil, h₂ = Enthalpy of air leaving the heating coil and h_A = Enthalpy of air at the end of humidification process)

A

$$\frac{{{{\text{h}}_{\text{A}}} - {{\text{h}}_2}}}{{{{\text{h}}_1} - {{\text{h}}_2}}}$$

B

$$\frac{{{{\text{h}}_2} - {{\text{h}}_{\text{A}}}}}{{{{\text{h}}_1} - {{\text{h}}_2}}}$$

C

$$\frac{{{{\text{h}}_1} - {{\text{h}}_2}}}{{{{\text{h}}_{\text{A}}} - {{\text{h}}_2}}}$$

D

$$\frac{{{{\text{h}}_{\text{A}}} - {{\text{h}}_1}}}{{{{\text{h}}_2} - {{\text{h}}_1}}}$$

Heating of an ore below its melting point in presence of excess of air is called

A

Calcination

B

Smelting

C

Roasting

D

Sublimation

The atmospheric air at dry bulb temperature of 15°C enters a heating coil maintained at 40°C. The air leaves the heating coil at 25°C. The bypass factor of the heating coil is

A

0.376

B

0.4

C

0.6

D

0.67

Which of the following is not a pyrite ore?

A

Celestite

B

Galena

C

Gypsum

D

Siderite

What percentage of SiO2 is present in Indian pyrite ore?

A

5-7%

B

10-12%

C

16-19%

D

20-21%

Sulphur removal by heating of pyrite ore in presence of air is called its

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