What is a Geological Repository?

Tellus is developing geological repositories because due to our economy and modern lifestyle, Australia is one of the highest emitters of hazardous waste per capita and there is insufficient infrastructure nationally at competitive price points to manage the rapidly growing problem from legacy, production and emerging hazardous waste types.

We need to deliver innovative solutions for the safe management of these difficult to manage waste types that may be harmful to the environment or human health not just for decades but for some types of waste like heavy metals that NEVER break down and lose their hazardous nature. Therefore, we need facilities that can meet today’s safety requirements as well as protecting ourselves, and future generations well into the future.

Geological repositories are highly engineered facilities with multiple man-made and natural barriers and a facility layout that can primarily offer permanent isolation (disposal) of equipment, hazardous materials and waste from the biosphere over geological time. With additional in-ground and surface infrastructure they can also provide long term storage (retrievable) and treatment, recycle and recovery services.

1. The key difference between a landfill and a geological repository is that landfills rely on man-made containment barriers which ultimately fail over time and therefore cannot permanently isolate the waste. A geological repository relies on the natural geological barriers to isolate the materials from the biosphere and hence can permanently isolate the waste for hundreds of thousands to millions of years. Since a geological repository can pass the “Passive Safety Test” there is no requirement to actively maintain the facility after the Institutional Control Period. Hence there is no material risk passed on to future generations. This can not be said for landfills and there are thousands of landfills across Australia, either presently leaking or likely to in the near future
2. Fun facts about Sandy Ridge’s geology that makes the site so unique? Sandy Ridge is part of a 70-million-year-old kaolin clay bed, on top of some of the oldest and most stable rocks on earth which formed ~ 3.7 billion years ago. The facility is located 240 kilometres by road west north west of Kalgoorlie

Hazardous waste is a waste with properties that make it potentially harmful to human health or the environment.

Tellus has very strict waste acceptance criteria that is highly regulated. Of the waste types managed, the majority is chemical waste like contaminated soils, scrubber residues, top and bottom fly ash, asbestos from the construction, metal refining and power sectors. The next largest category are metals, acids and alkalines from the remediation industry, mining, oil & gas, manufacturing, utilities (e.g. power, water and telecoms). Tellus also accepts waste from man-made and natural disasters.

The implementation of Sandy Ridge Facility would result in the following positive social and economic benefits to Western Australia and, to Australia in general:

• Provides safe management solutions for difficult to manage hazardous waste resources
• Future potential recovery of valuable materials (that are currently deemed waste)
• Long-term jobs
• Major investment
• Business opportunities in remote regional Australia
• Diversification of the economy
• Royalties, taxes and levies generates wealth that is used to pay for Government services
• Long project life of 25 plus years. The site can be expanded for generations
• Opportunities for training, employment and business opportunities for indigenous community
• Critical piece of enabling infrastructure

Tellus geological repositories use environmentally sound management (‘ESM’) principles and can also support the circular economy.

ESM principals

ESM principals protect both the environment and human health. ESM includes materials that cannot be recycled, recovered, or are residual materials from the recovery process that should be disposed of in world’s best practice geological repositories that isolate the waste from the biosphere.

Geological repositories have historically been used in the safe storage of difficult to manage wastes, largely radioactive waste from the 1960’s, involving near surface storage or disposal for lower risk and lower activity levels eg. half-life of 30 years or less. Higher risk and higher activity levels of waste have typically been disposed of in deeper storage in geologically stable beds of crystalline rock, salt and clay

However, regulators and key stakeholders are beginning to recognise that the risks associated with hazardous chemical waste management, many of which never breakdown, need to be equal or greater than low level radioactive waste management. Germany has been trail blazing the disposal of chemical wastes in salt beds since the 1970’s. Other countries have since developed geological repositories for chem. and or rad. waste in clay and salt beds around the world. Countries that have near surface geological repositories include: Australia, Czech Republic, Finland, France, Japan, Netherlands, Spain, South Africa, Sweden, UK, and USA.

The Sandy Ridge facility is licenced to accept low level radioactive waste (LLW) including Naturally Occurring Radioactive Material (NORM) often found in minerals sands, rare earth and oil and gas processing facilities. The Sandy Ridge facility is also licenced to accept disused sealed radioactive sources (DSRS). Sealed radioactive sources are used in the construction, industrial processing and medical industries.

A safety case draws upon:

• Site selection and characteristics
• Organisational and technical arrangements
• Nature of the waste to be accepted
• Design of the facility, including its multi barrier system
• Construction, operation, decommissioning, closure and post-closure stages
• Risk assessment
• Assurance and insurance
• Must demonstrate the protection of people and the environment.

Tellus believes some wastes should be seen as a valuable resource and we should find ways for the materials to be recycled or recovered so it can re-enter the circular economy or stored safely until it can.

Tellus also supports the circular economy by storing ‘like-with-like’ materials to create opportunities for the future recovery of valuable materials.The opportunities presented due to economies of scale, storing “like with like” and looking at the materials on a molecular level is what Tellus believes is the key to converting the waste into a valuable resource and positioning Australia as a leader in high-value niche products.

We can achieve this only if researchers, industries, waste generators and the waste industry work together with a technology recovery toolbox that can recover new green materials, new intellectual property and associated science and technology-based products and services.

Tellus plans to host these technologies at our own circular economy parks, located at our facilities.

Types of geological repositoriesGeological repositories can be near surface (depths of tens of meters) or deep (depths of between 250m and 1000m).

Key features

The main unique key features or capability of both the near surface or deep repository is that they can provide the final resting place or the highest level of containment for hazardous waste (chemical waste) and low-level radioactive waste (LLW).

This is achieved through a combination of carefully selected active (man-made engineered barriers) and passive control measures (natural barriers) and the facility layout. This is known as a multi-barrier system.

Engineered barriers includes the waste form, the waste container, void buffer or backfill, bulk backfill (if open cut) and sealing systems (capped with an impermeable membrane and topsoil if open cut or plugs and seals if underground). The exact nature of the engineered barriers can depend on the waste type.

The natural barrier comprises dry, thick, flat, stable salt or clay formations.

The facility layout is the spacing between the voids (spacing between open cut pits or spacing between rooms underground)

Tellus’ multi barrier safety case relies on multiple fail-safe mechanisms but the best barrier of them all is the natural barrier with its passive control mechanism. The carefully selected site and host rock which does not require ongoing maintenance or monitoring is the fundamental property of geological waste repositories, which remain passively safe through geological time.