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Understanding the environmental and health

considerations of repurposing mine tailing for bricks

making

Responsible Mining and Resilient Communities

RMRC Project

Tailing pond in Las Partidas, Andes. Photo credit: Author

José Velásquez

Mining and Metallurgical Engineer

Civil Engineering Dept.

University of Texas at Arlington

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Mercury and mining

• Mercury contamination from ASGM operations is an

environmental, health and safety concern for communities and

government. (UNEP, 2019)

• An example of a source of mercury contamination from ASGM

is mine tailings left over from gold ore processing.

• One option to reduce mercury contamination is the

repurposing of mine tailings material as aggregate for bricks

production. (Roy, Adhikari, & Gupta, 2007)

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Potential environmental and health

concerns of mine tailing reuse

According to the EPA, hazardous waste is a material with

chemical characteristics that may pose a risk for humans and

other organism’s health when not disposed properly (EPA, 2005).

Occupational Health Standards for Hg (TWA)

Organization Concentration (µg/m3)

OSHA 100

NIOSH 50

American Conference of Government Industrial

Hygienists (ACGIH)

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Agency for Toxic Substances and Disease Registry

(ATSDR)

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EPA 0.3

(Garcia-Sanchez et al., 2006)

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Potential environmental and health

concerns of mine tailing reuse

From the GHS (Global Harmonized System) of the UN the

exposure to hazardous materials is subjected to its source and

media, classified as acute toxicity and chronic toxicity

(repeated and long exposure). (UNECE, 2019)

Exposure Route:

Dermal

Oral

Inhalation

Ingestion

Dust

Mist

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Past Initiatives

The main analysis that has previously been done on

Mine Tailings Bricks (MTBs) are based on:

Technical knowledge

Environmental exposure

Human exposure to Hg

Cost viability

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Past Initiatives (con’t)

• Technical knowledge: different techniques and

technologies such as geopolymerization and additive

have been studied in the brickmaking process to

immobilize hazardous particles (Ahmari & Zhang,

2012).

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Past Initiatives (con’t)

• Environmental exposure: Mercury volatilization,

transport and fate of contaminants (Lu, Hsu, & Lin, 2019).

• Human exposure to Hg: Health issues, methylmercury

and bioaccumulation factors (Cruz-Esquivel et al., 2019).

• Cost viability: Case studies using different methods of

fabrication (Roy et al., 2007).

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Andes case study

• One “entable” owner is trying to develop a method to

repurpose bricks out of gold mine tailings.

• Prior to implementation of these bricks is important to know

environmental, health and safety issues associated with mine

tailings bricks (MTBs)

• Edilber has been working with the “Universidad de Antioquia”,

analyzing the bricks through chemical tests (not specified).

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Can bricks created out of mine tailings that have been

exposed to mercury be safely implemented in community

construction initiatives?

Do the MTBs pose a chemical or

physical hazard for people using them ?

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Main aspects

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• ASTM D7886-14

Based on the testing protocol for asbestos, the American

Society of Testing Materials has developed standard

practices for exposure assessments.

As part of the exposure routes, is important to determine the

potential effects of human health with dust or volatilization

that may occur within the bricks structure.

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• TCLP Test

Toxicity characteristic leaching procedure – Is a standardized test that determines

the mobility of the contaminants, in this case Mercury (Hg).

The idea to perform this analysis is to test under the worst case scenario the

exposure to contaminants that may be experienced by the community from the

use of the bricks.

Crush the materialMix with chemical to create leachate.

Analysis with Spectrophotometry

Compare results with standards

Metal Values TCLP Max. values

Mercury (Hg) D009 0.2 ppm

Arsenic (As) D004 5.0 ppm

Lead (Pb) D008 5.0 ppm

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Methods

The idea is to analyze 9 bricks

samples made out of 3 different

tailings ponds, using the same Hg

extraction method. (The method

Edilber thinks is the most effective).

Measurement of elemental Hg in the air, Photo credit: Caitlin

Items Quantity

Bricks x9 500g

Tailings 500g

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Deliverables

• From the test we can deliver a technical report based on

the amount of mercury leaching out of the bricks from the

TCLP test.

• Power point presentation

• The results can help understand the process from the

mobility point of view, and will either have a good result

for Edilber’s process or a negative result implying the

need for more assistance and support for the processes

he is carrying out.

– Will serve as a comparison result for the Universidad de Antioquia

results.

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