Reference no: EM132470574

SCMET3100 - Mineral Processing - Federation University

Part 1:

Question 1
Consider a goethite ore assaying around 21% which needs to be routinely sampling to a confidence level of ±0.2% Fe 92 times out of 100. Pyrite is liberated as a particle size of 300 micron. Calculate the mass of sample required to be collected if maximum particle size is 3.5mm.

Question 2
Regular samples were required of the feed to a copper processing plant, having a copper content of about 7%. The confidence level of estimation was required to be 0.1 % Cu at 2s standard deviation. The liberation size of the Cu mineral (azurite) in the ore was determined to be 85 um. The top size of the ore from the sampler was 3.5 cm. Determine the minimum mass of sample required to represent the ore. Given; the density of azurite is 3770 kg/m³ and the density of the gangue is 2500 kg/m³.

Question 3
Consider a lead ore assaying around 5% Pb, which needs to be routinely sampled to a confidence level of 30.1% Pb, 95 times out of 100. The galena is liberated from the quartz gangue at a particle size of 150um.

Question 4
Iron ore was sampled before stock piling with a stacker. One hundred samples taken from the stacker-conveyor showed a standard deviation in the iron assay of ± 0.5 %. The ore assayed, on average, 55 % Fe. Sieve analysis of the samples showed that the largest size was less than 9 mm and the liberation of Fe was maximum in the size range, -400 + 300 microns. Given that the specific gravity of the ore was 5.4 and the specific gravity of the gangue was 2.6, estimate the minimum mass of sample required representing the stack.

Part 2:

Question 1

A screen produces an oversize product having the following size distribution:

Size (pm)	Oversize Mass%%	Undersize Mass %
-7000+5000	35.0	0.49
5000+3900	31.9	1.05
-3900+2500	12.0	9.5
-2500+1000	7.9	12.7
-1000+700	5.7	15.0
-700+500	3.9	17.8
-500+250	1.7	19.0
-250+125	1.8	22.9
-125	0.1	1.6

1. If the mass split of the feed to the undersize is 0.41, construct a Tromp curve for the separation.
2. Estimate the separation size of the screen.
3. What is partition error?
4. Plot cumulative percent passing using the Gates-Gauding-Schuhmann plot.
5. What is 80% passing size for the material?
6. Calculate recovery (Partition coefficient) of 250 pm particles to the underflow.

Question 2

A screen (aperture 7000 mm) overflow and underflow were sampled and these streams analysed to give the following size data. Determine the efficiency of the screen.

Aperture mm	Underflow Mass, kg	Overflow Mass, kg
+13300	6.6	1.3
-13300+4750	2.5	7.0
-4750+2360	5.5	7.4
-2360+1180	8.9	9.2
-1880+600	3.6	10.0
-600+300	5.4	9.6
+300-150	2.7	5.7
-150+75	1.4	5.2
-75	1.1	9.7