Despite border closures, more than 2400 delegates are expected to attend over three days.
"Sadly, due to border closures and travel restrictions, our international delegates and most of our interstate delegates are unable to attend again this year," Walker said.
"We are hopeful that the entire Diggers and Dealers family can be together next year - that will be cause for celebration."
Diggers will live stream this year's presentations to those who could not attend.
"We are incredibly proud to be back in Kalgoorlie celebrating the 30th anniversary of Diggers & Dealers," Walker said.
"Within a 50km radius of this stage, the entire lifecycle of mining and exploration companies is playing out.
"From grassroots exploration to mineral production - every occupation represented in this room is playing a role.
"Right across Australia, in regional towns just like Kalgoorlie, the mining industry is thriving and powering our economy.
"Over the next three days, let us all celebrate Kalgoorlie-Boulder and the mining industry."
Walker paid tribute to the late Dr Roy Woodall. His wife Barbara had planned to attend the conference until border closures prevented it.
Walker also used his opening address to promote education and encouraged delegates to support the CoRE Learning Foundation.
"I am fortunate enough to have had a rewarding career in the mining industry that has allowed me to meet some incredible people and travel the world and I'm a strong advocate for the mining sector and have encouraged my children and my grandchildren to consider a career in the industry," he said.
"Encouraging the next generation to pursue a career in the mining industry is becoming a lot easier as the community is beginning to recognise our contribution.
"This is not based purely on our huge economic contribution but also through the understanding that we produce all the minerals required for future growth in renewable energy production, battery storage and electric vehicle manufacturing.
"Along with our encouragement and the growing appeal of working in the resources sector, education pathways are being established for school students."
Professor Ian Goldin delivered a keynote virtually from his base in Oxford. He predicted in 2014 that a global pandemic would be the cause of the next financial crisis.
He told the crowd they had the power to solve many of the world's problems.
Goldin predicted hunger would kill more people than COVID-19 and called for further stimulus measures.
He said a Cold War with China was his greatest fear, as none of the world's problems could be solved without China.
