Acid Mine Drainage

Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines or coal mines.

Acid rock drainage occurs naturally within some environments as part of the rock weathering process but is exacerbated by large-scale earth disturbances characteristic of mining and other large construction activities, usually within rocks containing an abundance of sulfide minerals. Areas where the earth has been disturbed (e.g. construction sites, subdivisions, and transportation corridors) may create acid rock drainage. In many localities, the liquid that drains from coal stocks, coal handling facilities, coal washeries, and coal waste tips can be highly acidic, and in such cases it is treated as acid rock drainage. This liquid often contains toxic metals, such as copper or iron. These, combined with reduced pH, have a detrimental impact on the streams aquatic environments.

On the 25th June 2019, the COHWHS Association met with Mariette Liefferink - CEO: FEDERATION FOR A SUSTAINABLE ENVIRONMENT with regards to current status of AMD water treatment plant and pump station at the Mintails mine on West Rand.

Mariette sent us the email below and the presentation is available at the bottom of this page. 

From: Mariette Liefferink


Dear Sirs, 

I write on behalf of the FSE and Cradle of Humankind World Heritage Site Association (Registration Number: 2012/001920/08), whom I copy on this e-mail. 

Pursuant to our meeting on the 25th of June, 2019 and my presentation (attached hereto), which included the Press Statement by the TCTA, I undertook to keep the Association’s members updated on the status of the AMD Water Treatment Plant and Pump Station. In order not to propagate inaccuracies, I hereby respectfully request information on the current status of the plant and pumping station including the criminal activities at Mintails’ gold treatment plant. 

In anticipation, please accept our sincere thanks. 

Best Regards 

Mariette Liefferink


The Trans Caledon Tunnel Authority says that its acid mine drainage water treatment plant in the Western Basin couldn’t be re opened as planned on 4 June 2019 due to an escalating security threat in the Mintails Gold Treatment plant area

The AMD Western Basin has been out of commission since 24 May 2019 due to cable theft and general vandalism caused by illegal miners in the neighbouring Mintails Gold Treatment plant area

The theft and vandalism led to a power failure at the pump station on 9 Shaft, leading to the shutdown

The situation arose when illegal miners took possession of the Mintails mining site, adjacent to 9 Shaft which houses the AMD pump station The Mintails site was previously secured, however, when it was placed under business rescue the appointed liquidators withdrew the security services, paving the way for illegal miners to step in

The Eskom substation which supplies power to the pump station is located on the Mintails site. 

TCTA reported through a local newspaper on Saturday 1 June 2019, that it expected to have the plant re opened by 04 June 2019. TCTA, in collaboration with Sibanye Stillwater, at the time had been in the process of rerouting the cable line through an overhead power line, meant to make the cables inaccessible to cable thieves and as a means to speed up the repair process.

However, as of Monday 3 June 2019, the solution had to be abandoned due to the deteriorating safety situation in the neighbouring area.

Contractors working on the line could not complete the work as a result of the rapid and drastic escalation of crime activity in the area. Most of the connection points at the Eskom substation had also been vandalised during this period, further placing doubt on the sustainability of the proposed solution.

"The area has become extremely dangerous for contractors and security personnel, with armed and dangerous illegal miners zama zamas running unhindered in the area and out numbering the security personnel on the ground The place is like a warzone", says TCTA Executive Manager Project Management and Implementation Johann Claassens, 

A new proposed plan is to draw electricity from an identified substation that is 3 7 km from the pump station

"It is expected that this solution will take approximately three to four weeks to be fully implemented, due to the distance and the virgin territory that must be prepared for the purposes of the new power line," says Claassens

TCTA and Sibanye Stillwater management had also looked at the possibility of installing a generator in order to reduce downtime, however, due to the power needs of the AMD plant and pump station this was considered unviable in the short to medium term as the size of the generator required is not readily available and would be costly

The water table is currently at approximately 8 600 mm below surface, rising at an average of 100 mm/day It is expected that by the time of operation the water level will have risen by about 2 100 mm putting it at approximately 5 860 mm below surface This would still be within the safe margins 

However, with the water table rising there is a risk of limited seepage of acid mine water into the wetland area downstream of the abstraction point due to the pumps located in the wetland also being impacted by the power outage

Of the three basins managed by the TCTA (AMD Eastern, AMD Central and AMD Western Basins) the Western Basin remains the most vulnerable due to the closing of the Mintails mines and the growing security threat posed by the illegal gold mining activities in the area

TCTA says that it is working closely with Sibanye Stillwater and Eskom to speed up the process of restoring power to the AMD Western Basin plant

"We continue to strictly monitor the water levels during this period and will implement all possible measures necessary to prevent decant of AMD into the environment," Claassens concludes

Mariette Liefferink's
Cradle Of Humankind Presentation
(8.58 Mb PDF)
25 JUNE 2019 

Download Document

IOL Article:
Illegal miners hit Mintails mine
on West Rand (External link)
1 June 2019

Exteranl Link