Dentons is suing the Republic of Guinea for more than $10 million in allegedly unpaid legal bills, plus interest.

In a lawsuit filed on Friday in the U.S. District Court for the District of Columbia, the firm said it was hired in 2012 to work with Guinea on the development of a large mining and infrastructure project. Guinea didn’t object to Dentons’ work or its invoices, the firm claimed, but never paid what it owed in fees and costs.

“We regret the need to resort to litigation to ensure we are paid for the value we provided to the Republic of Guinea and its people on this important project,” a Dentons spokeswoman said in a statement. She declined to comment on the details of the dispute, citing the pending lawsuit. Williams & Connolly partner Michael Sundermeyer represents the firm.

A representative from the embassy of the Republic of Guinea in Washington could not immediately be reached for comment on Monday.

The fee dispute stems from Guinea’s plans to develop large iron ore mines in the southeastern part of the country, known as the Simandou Project. According to the complaint, Dentons was hired to provide legal services to Guinea in connection with the mining project and an agreement between Guinea and one of the project’s investors, Rio Tinto.

The Dentons team was led by Washington-based partner Jonathan Cahn. The firm says it spent more than 10,000 hours on the Guinea matter from May 2012 to June 2013. The invoices totaled more than $12 million, according to the complaint.

In April 2013, Dentons said that Guinea paid the firm $2 million. The firm claimed all sides understood this was meant as only a partial payment of what Guinea still owed. Officials in Guinea repeatedly acknowledged the firm’s invoices and said they would pay, but did not, according to the complaint.

In August 2013, Cahn and a Dentons team traveled to Guinea to meet with officials about the outstanding legal bills. A government minister allegedly told the Dentons lawyers that the government hadn’t budgeted for the attorney fees it owed, but would seek funding from the World Bank and, if that money didn’t cover the expenses, the government would pay.

Dentons alleged Guinea stopped efforts to secure funding as of September 2013.

According to a copy of the retainer agreement filed with Dentons’ complaint, the firm charged hourly rates between $700 to $1,000 for partners in Washington, London and Paris; $700 to $850 for senior advisors in Washington; $600 to $700 for of counsel in Washington and Paris; and $200 to $550 for associates in Washington, London and Paris.

Dentons took in $1.26 billion in gross revenue in 2013, according to the latest Am Law 100 survey.

The case is assigned to U.S. District Judge Rosemary Collyer. No hearings have been scheduled.

Contact Zoe Tillman at ztillman@alm.com. On Twitter: @zoetillman.