What is a geological repository?

Tellus Holdings Ltd’s Richard McAree explains how the company is contributing towards a cleaner Australia by developing a portfolio of geological repositories.

An intergenerational opportunity to manage Australia’s hazardous waste has been making significant progress in the last few months. 

In June 2018, the WA Government Environment Minister approved the Sandy Ridge Facility, Australia’s first commercial geological repository. The facility will be built by infrastructure project development company Tellus Holdings (Tellus). In July/August the company’s mining lease was granted and early works commenced.

Geological repositories are facilities that provide a high level of containment for hazardous waste from the biosphere over geological time over hundreds of thousands to millions of years. This is achieved through a combination of carefully selected active and passive control measures – known as a multi-barrier system. The multi-barrier system can permanently isolate waste from the biosphere and protect the environment and human health. 

A geological repository and safety case relies on multiple fail-safe mechanisms underpinned by man-made barriers (active controls) and natural barriers (passive controls). Geological repositories rely mostly on passive controls which do not require ongoing monitoring as they can be quantified as being passively safe through geological time. 

Geological repositories have been operating in Europe since the 1970s and more recently in the UK, North and South America and Africa. According to Tellus, they are recognised globally as world’s best practice for the storage and/or permanent isolation of hazardous (chemical) waste and low-level radioactive waste.

The Sandy Ridge Facility, located 240 kilometres by road north-west of Kalgoorlie, will handle most solid and liquid wastes under the NEPM 75 categories, including contaminated soils from site remediation projects, PFAS, acids and alkaline wastes from industry. It will also handle arsenic and cyanide from the gold industry, hydrocarbon from the oil and gas industry and mercury and wastes generated by man-made or natural disasters. Sandy Ridge will also accept low level radioactive wastes such as naturally occurring radioactive materials from the oil and gas industry or disused sealed radioactive sources from diverse industries, including the health industry. Tellus will not be taking nuclear waste or intermediate or high-activity wastes. 

Located in a semi-arid environment, Tellus’ Sandy Ridge Facility is a near surface geological repository in a 70-million-year-old weathered granite kaolin clay bed. Sandy Ridge has been granted a 25-year license to mine 290,000 tonnes per annum (tpa) of kaolin clay and accept 100,000 tpa of capacity from around Australia and the Australian Exclusive Economic Zone. 

A second deep salt geological repository is also being developed 120 kilometres south of Alice Springs, NT. The Chandler Facility Project will involve the construction and operation of an underground salt mine in a 250-300-metre-thick, 500-million-year-old salt bed. 

One of the key drivers for Tellus in pursuing its geological repository business is filling a gap in the national hazardous waste market where there is currently insufficient infrastructure that deals with the problem permanently. 

Geological repositories typically have wide waste acceptance criteria and Tellus’ facilities can manage most hazardous waste types (NEPM 75) in different forms such as liquid, sludge or solid. 

Licenced facilities need to have adequate assurance, including bonds and bank guarantees and insurance, in place for not only the operation phase, but also the closure and institutional control period phase. This is to ensure that the state government is not out of pocket and the assurance needs to be fully costed, independently and regularly reviewed so there are no surprises.

Tellus’ repositories will be able to support Environmentally Sound Management (ESM) principles for medium to high hazard/risk wastes but can also present economies of scale to recycle and recover valuable materials that can support the circular economy. The waste operational procedures aligned with government-approved multi-barrier safety case allows Tellus to issue valuable Permanent Isolation Certificates (PIC’s).  

PIC’s can certify critical facts that may provide a basis for derecognising a liability provision on the financial statements under accounting standard AASB 137. PIC’s can also be used as evidence in compliance with regulations involved in environmental protection, product stewardship, occupational, health and safety and dangerous goods transport.

Tellus has engaged independent financial and legal advice to undertake the development of this process in line with its site selection, safety case design, operational procedures, insurance and assurance criteria associated with the facilities.

According to Blue Environment’s Hazardous Waste in Australia 2017 report, hazardous waste increased at a rate of nine per cent per year trending upwards in the years 2014-15. Hazardous waste encompasses nine per cent of all waste generated at about 64 million tonnes, according to data from the same period. 

Regulators and the community are demanding higher environmental, social and corporate government practices. Coupled with increasing personal liability for directors and senior employees and tightening Australian and international regulation and legislation, Tellus believes the current environmental climate requires a fresh and innovative approach. 

Richard McAree, General Manager – Business Development at Tellus, says the facilities will help solve the increasing financial, legal and technical issues surrounding Australia’s significant commercial and industrial hazardous waste problem. 

“Tellus is offering cost-effective solutions for the long-term storage, recovery and permanent isolation of hazardous waste, supported by environmentally sound management and a best practice safety case,” Richard says. 

“Our core reliance is on the geology, which has a very low permeability. We are working in large geological resources, in the form of an extensive, stable, flat, thick kaolin clay formation or a salt bed of the same characteristics,” Richard says.

“Critically, our Sandy Ridge geological repository does not have any exposure to groundwater aquifers or systems, so the risk of leakage or a pollution event to the broader environment is negligible.”

Richard adds that operating in a remote location, far from any human populations, also adds a layer of security to the operation. 

The Tellus team travelled internationally to undertake extensive studies into geological repositories and supporting infrastructure and have had the proposed Sandy Ridge and Chandler facilities extensively peer reviewed using local, national and international expertise.

“We’ve looked at and studied facilities in Germany, France, Canada, UK, USA and South Africa considering geology and hydrology, operational procedures and regulatory framework, including waste acceptance, cost base and service offering. Also of key interest is how they’ve managed to support the development of ancillary economic benefits such as a potential resource recovery options to support the circular economy.” 

“We have also learnt how geological repositories play their part in the waste hierarchy and have adapted to support international conventions such as the Stockholm, Minamata and Basel Conventions – three critical international legislative processes. Our safety case and operational procedures have been developed based on international best practice techniques to present Australia as a world leader for this type of infrastructure.”