Environmental impacts of small-scale miningborax gold extraction method Gold extraction with retort...

Environmental impacts of small-scale mining

Peter W. U. Appel

Common physical environmental problems caused by small-scale mining

• Deforestation

• Siltation of drainage system

• Land degradation

Deforestation

Siltation

”Washing” the cloth

Land degradation

Large scale vs small-scale

Health problems

• Dust

• Noise

• Cave in

• Chemical polution –mercury/cyanide

Dust = silicosisNoise = tinnitus

Gold extraction methods

• Gravitative e.g. Mali

• Mercury in modest amounts e.g. Tanzania

• Mercury in escessive amounts e.g. Philippines

• Cyanide e.g. Philippines

Mali – no mercury

Mercury pollution Tanzania vs Philippines

Mercury consumption in gold extraction

• In Tanzania ~ 1gram of mercuryfor 1 gram of gold

• In the Philippines >20 grams of mercury for 1 gram of gold

Tanzania – modest mercury

CrushingMilling

First step in gold extraction

”Washing” the clothSluicing

Amalgamation – last step in gold extraction

Tailings in Tanzania

<0.019.02OT-2C

<0.015.05OT-2B

0.587.51OT-2A

2.215.20OT-1C

2.156.85OT-1B

1.946.67OT-1A

Mercury g/tonGold g/tonSample no.

Mercury pollution Tanzania

Soil sampling

Soil samples Itumbi

0.24SS-6 7 km from Itumbi village

1.1SS-5 3.5 km from Itumbi village

0.76SS-4 In Itumbi village

0.57SS-3 In Itumbi village

0.29SS-2 In Itumbi village

3.54SS-.1 In Itumbi village

Mercury content g/tonSample no. and location

Mercury >0.5 g/ton is considered

dangerous

Soil samples Londoni

2.9SS-15 10 km from Londoni village

0.83SS-14 In Londoni village

0.69SS-13 In Londoni village

0.22SS-12 In Londoni village

0.31SS-11 In Londoni village

0.87SS-10 In Londoni village

0.77SS-9 In Londoni village

0,07SS-8 A km outside Londoni village

0.09SS-7 A km outside Londoni village

Mercury content g/tonSample no. and location

Mercury >0.5 g/ton is considered

dangerous

Lower values in Londoni compared to Itumbi may be because small-scale gold mining in Itumbi has gone on for many years

Philippinesexcessive mercury consumption

Mercury flour

Mercury (+ gold) is lost to the tailings

1101+Luklukan494859

7313+Casalugan494858

12014+Casalugan494857

20014+Sibutad494856

25016+Sibutad494855

Mercury g/ton

Gold g/ton

Aftercyanide

Beforecyanide

LocationSample no

Burning the tailings

How serious is mercury pollution?

Minamata in Japan

27 tons of mercury released over a period of 34 years

Thousands died and many more were crippled

In the Philippines

200 to 500 tons of mercury released every year from small-scale mining

How many will die and how many will be borne crippled?

Health problems caused by mercury

• Tremors

• Difficulty walking

• Tunnel vision

• Psylogical problems

• Cancer

• Death Pregnancies

12 year old Philippine girl severely mentally and physically crippled in pre-natal state by mercury

The mercury whichharmed her stemmed from

small-scale mining

What can be done to reduce mercurypollution?

Introduce recycling of mercury and/orborax gold extraction method

Gold extraction with retort

Borax method

Cyanide gold extraction

Small-scale miners cannever extract all their

gold. Mostly they loosein the order of 40%

Cyanide is a way out

Cleaning of tailings in the Philippines

State Battery

Leisure time in small-scale

miningcommunity

Home made pool for kids