School of Graduate Studies

School of Graduate Studies
School of Graduate Studies

Mine and refine – Meet Uchitta Vashist

MASc in Mining Engineering

by Phil Gaudreau

Uchitta Vashist

Cyanide gas can cause death in mere seconds, while ingesting cyanide can kill in minutes. The chemical is infamously featured in movies as a way for spies to escape capture. So why would mining companies be using cyanide for gold recovery, causing inevitable contamination in ground and water?

Well, it turns out, to extract one of the world’s most valuable substances you need to use one of the world’s most deadly.

Due to its high selectivity towards gold, cyanide typically helps gold companies recover as much as one hundred percent of the gold from most kinds of gold ores – making it the best solvent available. But, no matter how many environmental standards and practices are put in place, there is always a chance of some amount ending up in the tailings of the plants or leakage.

So, Uchitta Vashist (MSc’18) is working under Dr. Ahmad Ghahreman on a project with Barrick Gold’s Nevada operations. Barrick is one of the world’s largest gold miners and currently the only gold-thiosulfate leaching operation in the world. The goal of the project is to improve the gold recovery of the process using a more environmentally friendly and safe solvent.

“One of the best alternatives available for a certain kind of gold ore – the kind I am working with – is thiosulfate. Cyanide barely works on these ores called “refractory gold ore” and I'm working on increasing the recovery rate – which is typically in the 60 to 80 percent range,” she says. “It’s not currently commercially viable to use thiosulfate on the rest of the ores, in which case cyanide gives a better recovery with currently available technologies, but by adjusting different parameters of the process we can slowly increase that ratio.”

Uchitta finished her course-based masters of chemical engineering at Queen’s in 2018, and is building on that research by completing a masters in mining engineering. Her research focuses on hydrometallurgy – a technique that involves mixing a solvent and an ore in different conditions to try and extract the most metal possible.

Her interest in engineering was sparked by her sister, who is a software engineer back home in Gurgaon, India, and by some of her friends. “I was always interested in chemistry, so I thought chemical engineering would be a good combination of that,” she says.

After completing her masters in chemical engineering, Uchitta saw an interesting opportunity to leverage her knowledge and her supervisor’s connections with Barrick Gold to contribute to the thiosulfate project. She has quite enjoyed working in mining and hopes to increase her experience through work in the mining industry before deciding on her ultimate career path.

While there aren’t any mines in the Kingston area where Uchitta could ply her trade after graduation, she has enjoyed her time in Kingston – from the waterfront, to the small size and relaxed pace, and the nicer summer weather.

“It has been a drastic change for me to get to know so many people from so many different countries and cultures,” she says. “I would definitely recommend Queen's not just because of the course curriculum and the studies – which are excellent – but also because of how many opportunities are available. You can’t get bored here.”

Uchitta keeps busy outside of the lab through volunteering. In addition to working with the Society of Graduate and Professional Students, Uchitta helped found an Indian Graduate Students Club and is an amateur Bollywood dancer. She is also a student staff member at the Queen’s University International Centre – an experience she describes as highly rewarding, as it allows her to help international students at Queen’s to get settled into their studies and life in Kingston.

To learn more about graduate studies through the Robert M. Buchan Department of Mining, visit mine.queensu.ca.