Fehér Béla (szerk.): Az ásványok vonzásában, Tanulmányok a 60 éves Szakáll Sándor tiszteletére (Miskolc, 2014)

Móricz Ferenc - Mádai Ferenc - Walder Ingar F.: Szulfidos bányászati meddőkben lezajló piritoxidáció időbeni változása

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F. Móricz, F. Mádai &I.F. Wälder

Table I. Physical parameters and pyrite contents of the 7 samples analysed.

I. táblázat. Az elemzett 7 minta geotechnikai jellemzése és pirittartalma.

Sample

Minta

Residence time

(years)

Tartózkodási idő

(év)

Character

Jelleg

Grain size / main fraction

Szemcseméret / fő frakció

Pyrite content (from XRPD) Pirittartalom (XRPD alapján)

Bol 1

15-25

tailing

meddő

2-15 / 3-5 mm

2-3%

Bol 2

1-2

flotation tailing

flotációs meddő

0.1-1 / 0.3-0.5 mm

10-12%

Bol 3

15-25

tailing

meddő

2-15 / 3-5 mm

2-3%

Itos jig 1

15-25

jig tailing

mosási meddő

0.5-25 / 2-5 mm

6%

Itos jig 2

15-25

jig tailing

mosási meddő

0.5-25/2-5 mm

4%

Itos Granza 1

15-25

waste rock meddőkőzet

0.5-40 / 4-7 mm

5%

Itos Granza 2

15-25

waste rock meddőkőzet

0.5-40 / 4-7 mm

4%

and Bol 3 were similar. They were collected from the same waste heap, but from different parts.

The maturation state of the sample, i.e. the residence time under field conditions will affect on the time that is required to reach the steady state oxidation during the column test. Fresh sample needs more time to start oxidizing as well as longer column test investigation to reach a steady state pyrite oxidation rate compared to the already oxidized samples.

In Oruro there were no strict mining regulations, thus the composition and the size of the waste dumps and tailing heaps are not known. The age is also uncertain, so we have no exact information about the residence time of these samples, except Bol 2, which is relatively fresh sample, because it stayed only 1-2 years as tailing. From visual, macroscopic and stereo microscopic observation we have an assumption, that the samples were stored about 15-25 years, but this is only a rough estimation.

In the three-year test period, the length of the column test was different for the individual years. The two Itos jig samples together with the Itos Granza samples underwent 3 years of analysis that means 101 days in the first one, 42 days in the second and 114 days in the third one. Whereas the three Bol samples had no column test analysis in the first year, so they underwent analysis only in the second (42 days) and third (114 days) years.