Nearly half of all employees who responded to an external review of the miner's workplace culture commissioned by Rio Tinto said they had been bullied, while racism was found to be common across a number of areas.
Rio Tinto chief executive Jakob Stausholm said the results, published on Tuesday, were "disturbing" and the company would implement all 26 recommendations from the report by former Australian sex discrimination commissioner Elizabeth Broderick.
"The eye opener for me was two-fold," Mr Stausholm said.
"I hadn't realised how much bullying exists in the company and secondly that it's quite systemic - the three issues of bullying, sexual harassment and racism ... that's extremely disturbing."
Rio Tinto launched the review in March last year. More than 10,000 employees, nearly a quarter of its 45,000-strong workplace, shared their experiences and views for the study.
The report found nearly 30 per cent women and about seven per cent of men have experienced sexual harassment at work, with 21 women reported actual or attempted rape or sexual assault.
Racism was a "significant challenge" for employees at many locations.
People working in a country different to their birth experienced high rates of racism while nearly 40 per cent of men who identify as Aboriginal or Torres Strait Islander in Australia had experienced racism.
"I have copped racism in every single corner of this company," one employee was anonymously quoted as saying.
Rio Tinto said reforms will focus on a commitment from the company's leadership to create a safe and inclusive working environment, including by increasing diversity within the company.
It would also ensure the company's remote mine site facilities are safe, and make it easier for staff to call out unacceptable behaviours.
The Rio Tinto report comes ahead of the release of another report by the West Australian government later this year on sexual harassment at mining camps in the state.
In a 2020 report, an Australian Human Rights Commission inquiry into sexual harassment found 74 per cent of women in the mining industry had experienced some form of sexual harassment in the past five years, partly due to a gender imbalance.
Nearly 80 per cent of Rio Tinto's workforce is male.
"Creating a safe, respectful work culture will encourage people of all backgrounds and diversity to thrive in our organisations," Rio Tinto's Australian chief executive Kellie Parker told Reuters.
Male and female employees in South Africa experienced the highest rates of racism. Employees spoke of the frequency of racism and its impacts on their confidence, self-esteem and work performance.
"Rio is a Caucasian oriented company," one employee said in the report.
Rio Tinto said the report came at a pivotal time as workplace cultures shift against the backdrop of the Me Too, Black Lives Matter and other global movements, as well as an inquiry into the destruction of Juukan Gorge, culturally significant rock shelters.
