Digging deep for sustainable mining that mitigates climate change

During his 14 years at Monash, Professor Ranjith Pathegama Gamage has won a swag of innovation awards for his influential research into environmentally sustainable methods for extracting deep-earth resources like oil and gas that use carbon sequestration to combat climate change. His latest honour is a new Scopus Researcher Award from Elsevier for Excellence in Sustainability Research, which brings him a step closer to the ambitious goal that drives him. “My professional and personal goal is to contribute to our understanding of the world as responsible stewards of the planet,” Professor Ranjith says.

Professor Ranjith and his team pioneer creative, technically effective mining methods that often create useful by-products like fertiliser and green cement from waste. Their affordable, reliable method for extracting enhanced coal seam gas from otherwise un-mineable deep seams uses little water and releases methane for use while trapping carbon. This in turn has reduced carbon in the atmosphere, mitigating climate change, while transforming Australia’s abundant gas reserves into safe, sustainable energy.

“We know that over 80% of energy still comes from fossil fuel, and that fossil fuel will be the dominant energy supplier for at least few more decades,” Professor Ranjith says. “So we’re developing new technologies for unconventional gas like shale gas, tight gas and coal seam gas, which are very deep and difficult to extract, so they can be extracted economically and in an environmental friendly way.”

“Burying CO2 in deep underground is considered by many scientists and US engineering academics as the answer to large-scale reduction of CO2 levels in the atmosphere. It is one of the 21st century’s greatest engineering challenges”. Conventional mining is very energy intensive (over 10% of energy produced in the world is used for rock crushing and grinding) and therefore an alternate technology is required. In-situ leaching is a promising mining technology that can be enhanced by combination with suitably advanced rock-fracturing technology. We are now developing a disruptive technology-3G-DTM (3rd generation disruptive technology for mining-patent under pending) and the “results in the laboratory environment are very promising,” Professor Ranjith says. “I am confident that this technology will revolutionise mining in the future”. This 3G-DTM technology can be used in many other fields including renewable energy such as deep geothermal energy and unconventional oil and gas.

 

 

The main goal of this 1st IC3G2016 conference was to bring together experts of Geoenergy and Georesources areas from Academia and Industry from the globe to discuss the challenges faced in those industries and to discuss and discover new sciences and to develop new technologies for economical and environmentally friendly methodologies for extractions of resources and energy from the earth. The conference was well over attended by 200 attendees

There were many topics (unconventional oil/gas, mining and petroleum geomechanics as well as civil geotechnical eng) covered during the two days of the conference, and the presenters did an outstanding job of sharing the latest research findings with other researchers.

The next IC3G 2018 will be held in Sichuan city, China in September 2018. The website (www.ic3g.com) will be launched very soon.

 

  

  

  

  

 

The main goal of this 2nd IC3G2018 conference was to bring together experts of Geoenergy and Georesources areas from Academia and Industry from the globe to discuss the challenges faced in those industries and to discuss and discover new sciences and to develop new technologies for economical and environmentally friendly methodologies for extractions of resources and energy from the earth. The conference was well over attended by 200 attendees

There were many topics (unconventional oil/gas, mining and petroleum geomechanics as well as civil geotechnical eng) covered during the two days of the conference, and the presenters did an outstanding job of sharing the latest research findings with other researchers.

 

  

  

  

  

  

 

An interesting fact is that, according to the Department of Industry, Innovation and Science (DIIS), in the past ten years, the average annual growth of coal consumption in Australia decreased by 2% while that of natural gas increased by 4.1%. These statistics clearly illustrate that Australia is now transiting from coal to natural gas, considering the energy consumption. With these levels of dependence on natural gas, it is difficult to survive by only utilising conventional natural gas. Therefore, reservoir stimulation techniques need to be used in order to extract unconventional natural gases such as shale gas and tight gas. Of these technologies, foam-based fluid fracturing has the greatest potential to extract shale and tight gas effectively.

The recent studies reveal that, Foam-based fracturing fluid leads to a higher breakdown pressure of 26.3 MPa, which is about 29% higher than that of water (Fig.1). This is mainly due to the high viscosity of foam (150 mPa·s), which is about 200 times greater than that of water. Also the results show that the fracture pattern induced by hydraulic fracturing is significantly fracture fluid-dependent, and foam-based fluid generates a complex fracture with a twisted nature and higher fracture surface area compared to water (Fig.2). Therefore, the use of foam-based fracturing fluid is favourable for the extraction of greater amounts of natural gas. Moreover, the energy released in foam-based fracturing is about 10 times higher compared to conventional water-based fracturing, which is a favourable condition to enhance secondary and micro-fractures in the reservoir rock. This will enhance the productivity of the fracture treatment for natural gas production.

Experiments have been conducted using shale samples to investigate the effect of fracturing fluid injection flow-rate on hydraulic fracturing and associated fracture characteristics. Results reveal that the breakdown pressure of shale increases with increasing foam injection flow-rate due to the penetration of disintegrated gas into the rock (Fig.3). This is caused by the destabilisation of foam when it is in contact with reservoir rock. In addition, the time to achieve breakdown decreases, while the total foam consumption increases with increasing injection flow-rate. For example, an increase of foam injection flowrate from 10 to 70 ml/min causes the breakdown time to decrease by 80% while the foam consumption for fracturing increases by 40%. Therefore, concerning the economic aspects of hydraulic fracturing, low injection flow-rates are much more economical than high injection flow-rates.

 

  

Fig.1. Variation of (a) inlet pressure and (b) cumulative energy, with time for water- and foam-fractured specimens (W1 and F1).

 

  

Fig.2. Surface topography of foam-fractured specimen (a) 3-D view (b) 2-D view with surface contours (All units are in mm).

 

  

Fig.3. Variation of the bottom hole pressure with time for different flowrate conditions

 

 

Fig.4. Fracture pattern before and after the hydraulic fracturing with different injection flowrates

 

 

 

We are grateful for the enormous support you have extended to us through the years both in easy and in difficult times. It is with regret we bid you farewell, but with excitement and ecstasy we wish you all the very best in your future endeavours. Bon Voyage.

 

  

The potential of internal stability of granular soils can be evaluated using the three commonly used semi-empirical criteria: Kezdi (1969), Sherard (1979), and Kenney and Lau (1985). However, some issues exist and need to be addressed. 1) Only limited particle size distribution (PSD) data can be obtained using sieving analysis technique. 2) Some specific PSD data is necessary but difficult to be obtained through sieve analysis. 3) The secant slopes of PSD curves only can be computed manually.


Therefore, a software package named Analysis Software for Internal Stability of Granular Soils (ASISGS) was developed to address these problems. The ASISGS program was divided into two parts: ① Calculation Program for Parameter Values of PSD Models (CPPV), which is used to develop an optimal parametric model for representing the PSD curves of granular soils based on limited experimental data. ② Calculation Program for Secant Slope of PSD Models (CPSS), which can be used to calculate automatically the secant slopes of PSD curves according to the three commonly used semi-empirical criteria, so that the internal stability of granular soils which mainly depend on soil PSDs can be evaluated.

 

Prof Yasuhiro Fujimitsu from Kyushu University visited the 3GDeep Lab in April to initiate collaborative research works on Geothermal between Monash University and Kyushu University, Japan.

 

On 16th December 2014, Vice Chancellor of Universiti Teknologi Petronas (UTP) visited the 3GDeep Research Laboratory with other Malaysian delegates.

 

Datuk Ir. Dr. Abdul Rahim Hashim – Vice Chancellor

Solihuddin Ahmad Nasarudin – Registrar

Mohd Hatta Amran – Manager, Lab Facilities Services Department

Noor Affendy Mohamed Ali – Manager, Human Resources Management Department

 

 

 

On 02nd February 2015, high-school students that are finalists in the BHP Billiton Science and Engineering Awards, visited the 3GDeep Research Laboratory.

 

 

The International Society of Rock Mechanics (ISRM) annually awards a bronze medal and a cash prize for the World Best PhD Thesis in Rock Mechanics in memory of Professor Manuel Rocha, the second President and organiser of the first international congress of the ISRM. The wining thesis is selected based on; 1) Problem statement, 2) Appreciation of State of the Art, 3) Theoretical and/or practical advancements, 4) Verification of proposed solution and 5) Quality of Presentation of the thesis. The choice of the prize-winning thesis is the responsibility of the Rocha Award Committee, appointed by the President, chaired by the President, and including the Vice-Presidents and any others co-opted to assist in the review process. The committee then invite the Rocha Medal winner to attend the following ISRM conference as a guest to receive the award with providing all the expenses.