The 15-year-old Russian figure skater Kamila Valieva will learn on Monday whether she can remain at the Beijing Olympics, the Court of Arbitration for Sport (CAS) said, as questions grew over why it took six weeks for her failed drug test to come to light.

The doping scandal surrounding the prodigious teenager threatens to tarnish the Games after the build-up was overshadowed by concerns about Covid and human rights in China.

Valieva's Beijing Olympic fate is now in the hands of CAS, which will hold a hearing on Sunday.

Russia's Kamila Valieva trained on Friday in Beijing
Russia's Kamila Valieva trained on Friday in Beijing AFP / Anne-Christine POUJOULAT

"It is anticipated that the decision will be notified to the parties in the afternoon of Monday, 14 February," the top sports tribunal said in a statement.

That is just one day before Valieva is scheduled to compete in the women's individual competition.

Valieva, who starred as Russia won team gold in Beijing on Monday, tested positive for the banned substance trimetazidine after competing at an event in Saint Petersburg on December 25.

However, the International Testing Agency says the World Anti-Doping Agency-accredited laboratory in Stockholm only reported that Valieva had returned a positive case on February 8 -- the day after she won team gold.

Kamila Valieva is awaiting her fate at the Beijing Olympics
Kamila Valieva is awaiting her fate at the Beijing Olympics AFP / Anne-Christine POUJOULAT

In an interview with AFP, United States Anti-Doping Agency chief Travis Tygart questioned the delay.

"The failure to report a test taken in December until after the team event in the Games is a catastrophic failure of the system to protect the public, the integrity of the Games and clean athletes who had to compete," Tygart said.

Russia's anti-doping agency RUSADA said it had been informed that a sharp rise of Covid-19 infections at the start of the year was to blame for the delay.

Snow falls on the competitors in the snowboard mixed team cross quarter-finals on Saturday
Snow falls on the competitors in the snowboard mixed team cross quarter-finals on Saturday AFP / Marco BERTORELLO

Valieva practised in Beijing on Saturday.

The president of the Russian Figure Skating Federation, Alexander Gorchkov, said: "We have no doubts about the honesty of our athlete.

"We have to find out...what happened to the December 25 doping sample almost a month and a half after it was sent to a foreign laboratory."

The case is just the latest doping scandal surrounding Russian athletes at Olympic Games in recent years, which led to Russia as a country being banned for two years.

Kamila Valieva trained in Beijing as the furore around her grew
Kamila Valieva trained in Beijing as the furore around her grew AFP / Anne-Christine POUJOULAT

Russian competitors are taking part in Beijing under the flag of the Russian Olympic Committee (ROC), providing have been able to prove they were not tainted by a massive state-sponsored doping programme focused on the 2014 Sochi Olympics.

The USA's Lindsey Jacobellis and Nick Baumgartner won the snowboard mixed team cross despite being the oldest pair in the event
The USA's Lindsey Jacobellis and Nick Baumgartner won the snowboard mixed team cross despite being the oldest pair in the event AFP / Marco BERTORELLO

Six golds were up for grabs on the eighth day of competition, in biathlon, cross-country skiing, skeleton, ski jumping, snowboarding and speed skating.

US pair Lindsey Jacobellis and Nick Baumgartner -- who with a combined age of 76 were the oldest pair in the event -- triumphed in the mixed team snowboard cross final.

It was a second gold of this Games for Jacobellis.

Baumgartner, 40, said experience had been key. "That's something about being the veterans," he said.

Gao Tingyu, who was the host nation's flagbearer at the opening ceremony, gave China its first men's Olympic speed skating gold when he took the 500m title in a new Olympic record of 34.32sec.

Jaclyn Narracott earned Australia's maiden Olympic medal in a sliding sport with silver in the women's skeleton, as Germany continued their domination with gold for Hannah Neise.

British-based Narracott waved an Australian flag in the finish area after taking silver with a time 0.62sec slower than the winner.

"Unreal, unbelievable, this means everything -- the medal, the childhood dream come true," said Narracott, who nearly quit in 2019 after suffering concussion.

"From a sliding point of view, to be the first is pretty cool."

Neise claimed the gold, meaning racers from Germany have grabbed nine of the available 18 medals in the sliding events so far.

In the night air of Zhangjiakou, north of Beijing, Marius Lindvik ended Norway's 58-year Olympic ski jumping individual title drought on the large hill, after he denied Japan's normal hill champion Ryoyu Kobayashi a golden double.

"It's pretty sick that I managed to perform two good jumps when it counts," said 23-year-old Lindvik.

Norway's first gold of the day came from biathlete Johannes Thingnes Boe, who won the 10-kilometre sprint.

French ice dancers Gabriella Papadakis and Guillaume Cizeron made an impressive start to their quest for Olympic gold, breaking their own world record to place top in rhythm dance.

In cross-country skiing, Russia's women took gold in the 4x5km relay, ahead of Germany and Sweden.

Norway and Germany each have eight golds at the top of the medals table.