Bauxite Residue Storage Efficiency
Bauxite Residue Storage Efficiency

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Landfilled Waste
Landfilled Waste

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Alumina Refining

 

Striving for a Cleaner Environment

 

We closely manage the emissions and waste we generate and continually look for innovative ways to either eliminate them at their source or effectively control them in compliance with applicable laws. We also evaluate improvements in technology for discharge treatment and control on a regular basis and share best practices.

 

Since establishing our strategic sustainability targets, we have made considerable progress toward the reduction of greenhouse gases, sulfur dioxide (SO2), nitrogen oxides (NOx), and waste disposed in landfills. We track our mercury emissions globally and continue to research cost-effective control technologies.

 

Our waste-related efforts focus on what we consider our most important issues—bauxite residue and landfilled waste.

Bauxite residue

Bauxite residue storage area in São Luís, Brazil

Bauxite Residue

Generated during alumina refining, bauxite residue is made up of two components of roughly equal quantity—sand and mud—along with some residual caustic soda. In 2013, we generated 27.3 million metric tons of residue, which is stored in impoundments that are capped and re-vegetated when full.

 

Our long-term strategic targets for bauxite residue are aimed at reducing the overall footprint associated with our management

of the material.

 

These goals are:

  • From a 2005 baseline, a 15% reduction in bauxite residue land requirements per unit of alumina produced by 2020; 30% by 2030;
  • Rehabilitate 30% of total bauxite residue storage area by 2020; 40% by 2030; and
  • Recycle or reuse 15% of bauxite residue generated by 2020; 30% by 2030.
Residue drying lake

Residue drying lake in Australia

 

In 2013, we met our 2020 goal for land requirements seven years ahead of schedule. To achieve the 2030 goal and our other targets, we have a comprehensive and ongoing research program aimed at continually improving residue storage practices to reduce potential environmental impacts. For example, we made the transition from wet storage ponds to an innovative dry stacking process in Western Australia in the 1980s. This technique has subsequently become accepted as an industry best practice.

 

We also have investigated ways to modify the residue, specifically decreasing its alkalinity to further lessen its potential environmental impact while enhancing its prospects of reuse.

 

Examples of our advances in bauxite residue modification and reuse include:

  • The Western Australia state government is continuing to investigate potential geo-sequestration of carbon dioxide (CO2) in the state’s southwest region. We have expressed interest in the project, as it could include the construction of a pipeline with the potential to deliver CO2 from the Kwinana industrial area to our Wagerup and Pinjarra refineries.
  • Alkaloam®: This fine-grained bauxite residue is carbonated through a reaction with carbon dioxide. An alkaline, Alkaloam increases soil pH similar to agricultural lime.  While traditional lime can take a number of years to effectively increase the pH of soil, Alkaloam can achieve the same result almost instantly. (View a research report on Alkaloam from the Centre for Sustainable Resource Processing.)
ReadyGrit

ReadyGrit is used in a bunker at an Australian golf course.

  • ReadyGrit: This red-colored crushed rock material can be used for general fill, construction backfill, turf top dressing, bunker sand, or a material suitable in road base construction. ReadyGrit could potentially reduce our global bauxite residue volume by one-fifth while providing an environmentally sound solution to Western Australia’s declining sand supplies. Since 2012, we have been working with our partners to conduct demonstration trials using the material from a pilot plant at our Kwinana Refinery.
  • Alkaline clay: We have been investigating the potential use of bauxite residue to treat coal-mining overburden that generates acid. Following three years of extensive full-scale pilot testing and analysis, the Pennsylvania Department of Environmental Protection in the United States issued a beneficial-use general permit for bauxite residue to be used in this type of application.

 

Our research is also focused on the rehabilitation of our bauxite residue storage areas, which are clay-sealed impoundments with underdrain collection systems. We control wind-blown dust from operating and open storage areas via water-spray systems.

 

We are improving the sustainability of the storage areas’ surface cover, and our locations are adopting best practice approaches for closure. While imported fill can be used to cap the areas, our research is focused on transforming the residue into a viable soil layer, which can sustain a vegetative cover and initiate in-situ remediation of the residue deposits.

 

We have a globally mandated policy involving the construction, management, and maintenance of our residue storage areas. An independent third-party professional also conducts an annual geo-technical inspection of the areas to ensure the operation is being maintained and operated to high standards. This is in addition to operating within local, regional, and federal standards.

 

Bauxite Residue Storage Efficiency
Square meters of land required per thousand metric tons of alumina produced
Goal: 15% reductionProgress: As of Dec. 2013 
15%

 

Bauxite Residue Storage Area Rehabilitation Rate
Percent of total area rehabilitated
Goal: 30% rehabilitatedProgress: As of Dec. 2013 
15%

 

Bauxite Residue Reuse
Percent of total residue generated
Goal: 15% reusedProgress: As of Dec. 2013 
0%

 

Bauxite Residue Intensity
Metric tons per metric ton of alumina produced

 

Landfilled Waste

Building on our early success in reducing waste, our current strategic target is a 75% reduction in landfilled waste by 2020 and 100% by 2030 from a 2005 baseline.

 

The goal excludes certain process waste streams from refining and power generation because the larger volumes of these materials, which include bauxite residue and fly ash, would mask our progress on reducing the landfilling of all other waste streams. We have separate programs and targets to address these large-volume wastes. In addition, overburden and rock generated from our mining activities are not included since both materials are reused in mine rehabilitation and are not considered waste.

 

To help reduce our landfilled waste, we are working with several partners interested in exploring opportunities for its reuse as feedstock that meets both technical specifications and regulatory requirements.

 

In 2013, we achieved a 24% reduction in landfilled waste from the baseline. We again saw an increase in waste volumes from certain facilities that we permanently decommissioned in recent years, and we worked hard to minimize these increases. Closure operations at the Tennessee Smelter in the United States, for example, resulted in the generation of additional landfilled waste.

 

Landfilled Waste
Thousands of metric tons
Goal: 75% reductionProgress: As of Dec. 2013 
24%

 

Total Wastes Sold or Recycled
Thousands of metric tons
Increase in 2011 was due to improvements in the recycling of spent pot lining and an increase in plant demolitions that resulted in significant recycled waste.

 

Spent Pot Lining

Spent pot lining (SPL)—a waste from our smelting process—is generated when the carbon and refractory lining of smelting pots reaches the end of its serviceable life.

 

We have led our industry in finding ways to transform SPL into a raw material for other industries. We work with cement manufacturers in countries around the world to implement environmentally safe processes that treat the chemicals of concern in the material and use SPL’s energy or raw material value to reduce the cost of cement production.

 

We continue to work on identifying opportunities to expand the market for this material, and this should allow for further increases in volumes recycled in the next few years. We are also developing measures to increase smelting cell life, resulting in fewer cell failures and fewer cells that need the lining removed and replaced. This pollution-prevention effort reduces operating costs and will result in less SPL for recycling or disposal.

 

Through these and other efforts, we recycled 62% of the SPL we produced in 2013, which represents a considerable improvement over the 52% recycled in 2012.

 

Spent Pot Lining Generated
Kilograms per metric ton of aluminum produced
The 2013, 2012, and 2011 generation rates do not include demolition tonnage from permanently idled smelters. The increase in 2011 was due to the additional SPL generated as a result of restarting smelters in 2011. The 2009 generation rate was considerably lower than typical years as a result of the curtailment of smelting production throughout the system.

 

Spent Pot Lining Recycled/Reused
Percent
The decreased recycling in 2011 and 2012 was due to lingering weakness in the cement industry and significant one-time remediation tonnage resulting from the permanent closure of several smelters for which recycling capacity was not available.

 

Air Emissions

We continue to pursue opportunities to reduce our various air emissions. (See the Climate Protection section for a discussion on greenhouse gases.)

 

The bulk of our mercury emissions occur in our refining operations because mercury is a naturally occurring element found in the bauxite we process in refining. There is considerable variation in the concentration of mercury depending on the source of the bauxite used, which creates a challenge for optimizing potential solutions aimed at reducing emissions.

 

We continued to research technological and operational solutions to achieve our strategic target of an 80% reduction in mercury emission intensity by 2020 and 90% by 2030 from a 2005 baseline. In 2013, our intensity decreased 29% from the prior year and 9% from the 2005 baseline mainly due to significant improvements in operational controls and decreasing levels of mercury in the bauxite processed.

 

In addition to mercury, we continue to identify innovative measures to reduce the emission of other pollutants, such as SO2, NOx, volatile organic compounds (VOCs), and fluoride. In 2013, the majority of these emissions declined slightly.

 

Mercury Emission Intensity
Grams per metric ton of alumina produced
Goal: 80% reductionProgress: As of Dec. 2013 
9%

 

Mercury Emissions
Thousands of kilograms

 

Sulfur Dioxide Emissions
Thousands of metric tons

 

Nitrogen Oxide Emissions
Thousands of metric tons

 

Volatile Organic Compounds Emissions
Thousands of metric tons

 

Fluoride Emissions
Kilograms per metric ton of aluminum produced

 

Ozone-depleting Substances

We continue to eliminate ozone-depleting substances from our process operations. In newly acquired facilities, elimination of these substances is a high priority. Although we use halon gas as a fire suppressant in several locations throughout the world, these systems will continue to be phased out. There have been no documented releases from a halon system since 2004.


Fugitive Emissions

Fugitive emissions, such as dust, are generally defined as those that are not emitted or released from a chimney, stack, or vent. Controls we use to manage or minimize fugitive emissions from our mining and process operations include the watering of haul roads, storage piles, and bauxite residue areas to suppress windblown dust. We also use capture and control systems for loading/unloading, material handling, aluminum reduction, and other process operations. We frequently employ visual-emission observation and ambient-air monitoring as tools to verify the effectiveness of these controls. 


Compliance

We maintain a very robust environmental compliance tracking system that ensures rapid corrective action of any noncompliance with applicable environmental laws and regulations. We also share best practices to ensure that all of our operating locations minimize the potential for unacceptable impacts to the environment.

 

Our corporate compliance function facilitates our goal of zero non-compliance incidents by tracking actual or potential issues and ensuring that matters of non-compliance are corrected with sustainable solutions.

 

We use an environmental permit review process to ensure that permit applications, draft permits, and final permits are effectively reviewed, commented on, and submitted in accordance with regulatory requirements. This beginning-to-end process facilitates receipt of final permits with conditions that are fully understood and achievable and allows for timely legal appeal of permit terms and conditions that are not achievable.

 

In 2013, 59% of our operating locations operated without any environmental non-compliance incidents, which is an increase from 48% in 2012.

Environmental Incident Rate
  Spills Over 20 Liters Major Spills Environmental Incident Rate per Location
2009 760   4 10.0
2010 599   2 9.2
2011 560   4 7.3
2012 562   9 10.1
2013 497   4 9.1

 

2013 Major Spills
Material Spilled
Volume
Liters
Environmental Impact
Process wastewater 100 Minor impact. No material released outside of the facility boundary. Some remediation required; no measurable residual contamination remains.
Caustic material/Bayer liquor 1,512,000 Moderate impact. No material released outside of the facility boundary. Some remediation required; no measurable residual contamination remains.
Condenser water 300,000 Minor impact. Some remediation required; no measurable residual contamination remains.
Oil 8 Minor impact. Some remediation required; no measurable residual contamination remains.

These spills were characterized as major environmental incidents according to our Environmental Incident Management System. They were not reported in our financial statements as significant spills, as they did not result in significant environmental harm or financial impact.

 

Environmental Capital Expenditures

We maintain a robust review process for all capital projects. Corporate environmental staff members review all requests for capital exceeding US$2 million to ensure that the work to be carried out incorporates best practices and the completed project minimizes additional impact on our environmental footprint.

 

Capital expenditures for environmental purposes fluctuate from year to year based on the number and type of projects implemented. Our expenditures, which decreased slightly in 2013 over the prior year, continue to be focused on environmental control system improvements.  These included improvements to material storage, management of impurities, water management systems, and control equipment.

 

Environmental Capital Expenditures
Millions of US dollars