Reference no: EM132650584

Question 1. A hard, abrasive, run-of-mine ore (2.78 g/cm³) will be crushed at a rate of 475 STPH with an OSS = 7 inches. Provide the following information, indicating which tables were used where appropriate:

a) Specifications of the minimum size crusher capable of meeting this requirement -

b) Percentage of crusher product passing 9, 6, and 3 inches -

c) Estimate of the specific energy -

d) Estimate of the reduction ratio -

Question 2. a) For the following devices, indicate under which category (Selective Splitter, Non-Selective Splitter, Blender, Modifier) each of the following devices would be placed (only one answer per device but the same category may be used more than once):

i) Thickener -

ii) Feeder breaker -

b) Estimate the recommended F80 for a 2836 jaw crusher with a throw = 2 inches.

c) Determine the model number for a roll crusher with the following: roll speed = 200 rpm, roll length = 2 feet, 100 hp motor, set = 2 inches, roll diameter = 3 feet

Question 3. A double-deck screen is being fed at a rate of 270 STPH. The feed material (ρs=3.1 g/cm3) fits the Rosin-Rammler distribution, which has a size modulus of 2.1 inches and a distribution modulus of 1.3. It will be wet screened at 1.5 inches and 0.25 inches using decks having open areas of 56% and 40%, respectively.

a) Show the ideal solid splits (in STPH) for each deck as would be used for the screen design. Include the relevant calculations -

3b) Determine the screen size based on the top deck only. Assume screens are available in widths of 4, 6, 8, and 10 feet. Include the bed depth check -

Question 4. A sample of a waste slag was screened into two size intervals. Each size interval was subjected to float-sink (specific gravity) separation. The -100+10 mm size interval contained 58% of the material (by weight), and the remainder of the material was contained in the -10+1 mm size interval. After float-sink separation, the specific gravity distribution (in weight %) for each size fraction was determined and is shown in the following table:

Specific Gravity Interval	Size Interval
	-100 + 10 mm	-10 + 1 mm
Float 2.6	67	46
2.6 x 3.0	24	33
3.0 Sink	9	21

a) Determine the joint distribution (give the values in % and to 2 decimal places) -

b) Determine the marginal specific gravity distribution (give the values in % and to 2 decimal
places) -

Question 5. The apparent density of a waste slag is 2.94 g/cm3. This slag consists of a mixture of a non-metallic material (ρ1 =2.63 g/cm3) and a metallic alloy (ρ2=6.85 g/cm3).

a) Calculate the volume fraction of the non-metallic alloy in the waste slag -

b) If a 55-gallon drum will be used to collect a sample of the material, calculate the weight (in kg) of the sample if the drum is filled with the material -

Question 6. Given the following size distribution:

Size Interval, mm	Weight %
-12+6	7
-6+3	33
-3+1.6	10
-1.6+0.80	37
-0.80+0.20	13

a) Determine the median size.

b) Determine the mode.

c) Determine the meansize by weight.