Proton collisions at the world's most powerful particle accelerator that some theorists say could create matter-consuming black holes should not be expected until the fall, a Russian physicist said Tuesday.

"We are not planning to begin proton collisions this summer," said Mikhail Kirsanov, a senior researcher at the Russian Institute for Nuclear Research, which is part of the Large Hadron Collider (LHC) project to investigate high energy particles and the beginning of the universe.

Some media sources have reported that the LHC may start "smashing atoms" as early as this week, and previous reports speculated that such collisions could create a black hole that would consume the Earth.

"We still have to cool down the accelerator and conduct some test-runs of proton beams around the accelerator ring," Kirsanov said. "No one can predict a certain date [for the start of the collisions]."

LHC is a particle accelerator that will collide opposing beams of protons together to explore the validity and limitations of the highly successful current theoretical picture for particle physics.

The $5.8 billion international project at the European Organization for Nuclear Research, known by its French initials CERN, involves more than 2,000 physicists from hundreds of universities and laboratories in 34 countries.

The accelerator complex, 27 kilometers in circumference, sits in a subterranean tunnel one hundred meters below the Franco-Swiss border, near Geneva, Switzerland.

Once it is up to speed, it is hoped the collider will produce the so-called Higgs boson, the observation of which could confirm the predictions and "missing links" in the Standard Model of physics and could explain how other elementary particles acquire properties such as mass.

Some theorists and members of the general public have long voiced fears that microscopic black holes may appear as a result of the experiment and capture the surrounding matter, ultimately leading to the destruction of the entire planet.

However, scientists have consistently dismissed these allegations as "ridiculous" - even if a microscopic black hole did form, they say, it would only last for a fraction of a second.

"Obviously, the world will not end when the LHC switches on," Lyn Evans, the head of the project at CERN, said last month.