1. Arsenic and Nitrogen handling in Mining Areas and Processes
Green Mining Seminar
EUROMINING 2013, Tampere
Raisa Neitola, GTK Mintec

2. Content GREEN MINING PROJECTS:
ARSENAL – Arsenic Control in Mining Processes and Extractive Industry
MINIMAN – Solutions for Control of Nitrogen Discharges at Mines and Quarries
Raisa Neitola, GTK Mintec

3. WHY WE NEED GREEN MINING PROJECTS?
The increased extraction of mineral resources and mining activities will place added pressure on the environmental issues and a proper water management in mining areas
The presence of arsenic and nitrogen compounds in mining areas and beneficiation processes creates the need to develop eco-efficient solutions to control different types of discharges in mining areas
ARSENAL and MINIMAN concentrate on developing technologies for management of arsenic and nitrogen discharges at the whole chain operations from quarrying and mining to end product and waste management.
Raisa Neitola, GTK Mintec

4. ARSENAL – Arsenic Control in Mining Processes and Extractive Industry
Timetable: Budget: k€
NEEDS
Arsenic is a world-wide challenge
Arsenic is commonly associated with ores containing metals such as gold
It is easily solubilized in water phase
Control of arsenic in all mining operations is a necessity
APPROACH
New mineral processing and water treatment solutions for arsenic removal
Novel bio-based treatment processes for arsenic containing wastes and streams
Monitoring and environmental risk assessment tools
BENEFITS
Better knowledge and new management tools on arsenic in the mining area
Eco-efficient solutions for mining industry to control and remove arsenic
Minimization of health and environmental risks related to arsenic
USERS & COMPETITION
Technology companies, mines, consults, authorities, other stakeholders
(Outotec Oyj, Kemira Oyj, Ekokem-Palvelu Oy, Agnico Eagle Oy, Endomines Oy, Nordic Mines AB, Pyhäsalmi Mine Oy, YARA Suomi Oy, Mondo Minerals B.V. Branch Finland)
Arsenic behavior is highly depend on prevailing conditions and processes
Special, tailor-made and global approaches are a challenge and a possibility
©Loukola-Ruskeeniemi,
Arseeni Suomen luonnossa ympäristövaikutukset ja riskit, 2004

5. WP1 Management of Arsenic in Beneficiation Process by Mineral Processing Methods
OBJECTIVES
To get preliminary understanding of the mineralogical and environmental characteristic of arsenic-containing tailings and their behiaviour in ponds
To develop beneficiation process to produce high quality gold concentrate with very low arsenic grade and environmentally friendly tailings
EXPERIMENTAL WORK
Mineralogical and chemical characterization of arsenic containing ores, concentrates and tailings by MLA and XRF
Environmental characteristic of As-containing tailings
Batch leaching tests, pH-dependency and static tests
Laboratory scale flotation tests for arsenic containing gold ores
OUTCOMES
Flotation flowsheet to produce
rougher high quality gold concentrate
scavencer As-containing marginal concentrate, which is later treated by bio- and cyanide leaching methods
Sulphide free and low arsenic containing tailings for disposal
Insight for tailings characteristics at disposal
Raisa Neitola, GTK Mintec

6. WP2 Sorption-based As-removal Technologies
OBJECTIVES
To develop techniques for removal of trace level As-concentrations as a polishing step before discharge to the environment
To find and apply cost-effective sorption materials for As-removal from mine waters
EXPERIMENTAL WORK
Batch tests with selected industrial by-products to assessment of sorption capacity and kinetics (commercial sorption material as reference)
Column experiments with real mine water to simulate the end-use application
OUTCOMES
Results suggest sorption to be a viable option for trace level As-removal from mine waters
Promising As-removal capacities found for pre-treated cast iron chips
Challenges remain in technical performance of the material (e.g clogging)
Raisa Neitola, GTK Mintec

7. WP3 Management of As-containing Side Streams and Waste Materials by Bioprocessing
OBJECTIVES
To develop biobased methods to process eco-efficiently industrial side stream
To reduce the amount of released arsenic and minimize environmental impacts of arsenic containing streams and waste materials
To stabilize arsenic from waste waters binding it into the iron precipitate
EXPERIMENTAL WORK
Mineralogical and chemical characterization of concentrates and bioleaching residues by MLA and XRF
Bioleaching of nickel concentrate, which is flotation by-products of talc production
Laboratory batch tests and continuous leaching tanks
Fluidized-bed reactor for waste waters
OUTCOMES
Knowledge and data for supporting the desing of
new industrial plant for utilization of arsenic bearing side stream
Treatment of arsenic-containing wastewaters through sorption
on biogenic iron precipitates was proved to be efficient
Stability of arsenic in the iron precipitate was pH-dependent
Raisa Neitola, GTK Mintec

8. WP4 Environmental research
Siilinjärvi
OBJECTIVES
To study and compare natural and anthropogenic As at two geologically different mine sites (Kittilä Suurikuusikko gold mine, Yara Siilinjärvi industrial area)
To assess and compare ecological risks at study sites
To model the behaviour of natural and anthropogenic As
EXPERIMENTAL WORK
Desk study of As geochemistry in mine environments
Water, soil and bedrock sampling & geochemical analysis
Modelling study (PHREEQC)
Assessment of ecological risks
OUTCOMES
Despite of the geology of mine site, mining activity has increased the proportion of available and potentially mobile As in soil
Mining activities have increased the ecological risks by
changing As into more soluble and mobile form
elevating As concentrations in the surrounding environment
As mobility in soil depends on adsorption by iron oxyhydroxides
Desorption of arsenic is potential risk to environment (e.g. wetlands)
Kittilä
Raisa Neitola, GTK Mintec

9. MINIMAN – Solutions for Control of Nitrogen Discharges at Mines and Quarries
Explosion fumes to air
Gases: N2, NOx
Spillage to surface and groundwater
Ions : NO3-, NH4+
Mined ore and waste rock
Remnants of explosives to the extraction facility → tailings
Remnants of explosives to the waste rock area → potential leaching
Final product
Timetable: Budget: 920 k€
NEEDS
Better understanding of the behaviour of nitrogen compounds
Minimizing of nitrogen transport
Removal of N-compounds from mine waters
APPROACH
Analysis of sources, behaviour and management opportunities of nitrogen compounds
Biological reactor process and electrochemical /adsorption process for nitrogen removal
BENEFITS
Knowledge, tools and technological solutions for nitrogen control at mines
USERS & COMPETITION
Technology companies, mines, consults, authorities, other stakeholders
(Outotec Oyj, Kemira Oyj, Ekokem-Palvelu Oy, Outokumpu Chrome Oy, Agnico Eagle Finland Oy, Yara Suomi Oy, FQM Kevitsa Mining Oy, Nordic Mines AB, Nordkalk Oy Ab, Infra ry, Kiviteollisuusliitto ry,
BK-automation Ky)
Non-nitrogen explosives/explosion techniques (not in near future)
Major nitrogen sources at mine sites
Ammonium nitrate based explosives
Cyanide used in gold extraction
Challenges
Behaviour and release of nitrogen compounds from waste rock and tailings
Water: Relatively low (NO3-, NH4+) concentrations, high volumes, high ionic concentrations, Nordic conditions

10. WP1 Removal of Nitrogen compounds by Biological techniques
OBJECTIVES
To evaluate the feasibility of biological methods to remove nitrate and ammonium from metal-rich mine wastewaters at low-pH
EXPERIMENTAL WORK
PCR/DGGE analysis for monitoring the evolution of microbial community
Batch tests for the assessment of metal toxicity and pH effect on microbial activity
Fluidized-bed and membrane bioreactors for denitrification and nitrication experiments
OUTCOMES SO FAR
Denitrification of acidic water is feasible whereas nitrification is more pH sensitive
Both nitrification and denitrification tolerate metal concentrations that are typical  in AMD

11. WP2 Nitrogen sorption experiments
OBJECTIVES
To find and apply cost-effective sorption materials for nitrogen compounds from mine waters
To compare different sorption materials and their ability to remove low concentrations of ammonia and nitrate from mine waters
EXPERIMENTAL WORK
Desk study of the potential sorption methods and materials based on existing knowledge
Batch and column tests using natural minerals based materials (e.g. zeolite, vermiculite) and other sorbent materials (e.g. carbon) with real/synthetic water
Regeneration tests of sorbent materials
OUTCOMES SO FAR
Zeolite sorption is potentially a functioning method of ammonia removal from mine waste water
Case dependant feasibility study and pilot scale testing are needed to confirm economics and feasibility
Natural zeolites are
hydrated aluminiosilicates with a three-dimensional structure and high
adsorption capacity.

12. WP3 Electrochemical nitrogen capture
OBJECTIVES
To develop novel electrochemical technique for nitrate and ammonia capture suitable also for Nordic conditions
EXPERIMENTAL WORK
Laboratory scale research using a continuous flow cassette reactor
Synthetic wastewater used in a self constructed reactor
Cooperation with University of Queensland Advanced Water Management Centre
OUTCOMES SO FAR
Electrochemically enhanced stripping is potentially a feasible technology for variety of inorganic streams for nitrogen capture in the future – including mine wastewaters
More research is needed for material selection and development and process optimization and reactor configuration
High ion concentration of mine waste water can cause fouling problems

13. WP4 Aging tests OUTCOMES SO FAR OBJECTIVES
To evaluate the nitrogen discharge from the mine sites
‘Nitrogen smudging’ (contamination by explosive originated nitrogen compounds) of otherwise mineralogically and chemically inert waste rocks of good technical quality hinders the utilization of these product streams
To gather essential data on the behaviour of nitrogenous compounds present in the environments of mines and quarries
EXPERIMENTAL WORK
Monitoring the surface waters around the quarries
Aging tests at the quarries
1000 m3 IBC-container + waste rock
OUTCOMES SO FAR
Data forms a basis for a holistic view on need and
options for nitrogen management in mining and quarrying that takes into account the scale of the operations
Mining activity seems to have relatively low nitrogen emissions, ”nitrogen smudging” should not prevent the utilization of waste rock material
The ”first flush” of nitrogen from waste rocks comes fast and is relatively short
(collected immediately after the excavation of a diabase block)

14. CONCLUSIONS
The results of ARSENAL project suggest that by novel mineral processing methods and proper water treatment methods the amount of As-compounds in tailings and effluents can be reduced to levels that satisfy the regulations concerning mining waste management.
So far, MINIMAN project generated new know-how on the behaviour of N compounds in mining areas and better understanding of the nitrogen discharge issue as well as developed advanced technologies for the removal of nitrogen compounds from mine waters.
Raisa Neitola, GTK Mintec

15. Thank You for Your Attention!
Raisa Neitola, GTK Mintec