It does not explicitly state that suppliers comply with companies' laws and policies.
pg. 11
"Employees across both businesses are expected to adhere to Banpu’s global company values and code of conduct."
pg. 12
"As Banpu Australia develop its approach to modern slavery, it will review the effectiveness of these initiatives and build upon them through further stakeholder engagement to raise awareness, training, supplier compliance ownership, ethical sourcing audit programs and grievance mechanisms, all aligned with our roadmap goals."
pg. 10
While it does not explicitly state that suppliers comply with company laws and policies, there the company has questioned its tier 1 suppliers on several topics and concluded that its tier 1 suppliers were at low risk of modern slavery.