The phrase "a difficult operation to" is correct and usable in written English.
It can be used when describing a task or procedure that requires significant effort or skill to accomplish.
Example: "Performing heart surgery is a difficult operation to master, requiring years of training and experience."
Alternatives: "a challenging task to" or "a complex procedure to".
He was scheduled to perform a difficult operation to remove an adrenal-gland tumor and wanted to practice his laparoscopic skills.
Inspector Dave Preston of Queensland police said it had been a difficult operation to get the man out of the mangled wreckage: "The fire and rescue had to do extensive work in relation to extracting and opening the vehicle up sufficiently to remove him.
It meant that Scotland avoided the worst deluge, although heavy showers did cause problems in the West Highlands, where engineers are facing a difficult operation to recover a 24-wagon freight train which came off the tracks between Corrour and Tulloch.
"It was a tremendously difficult operation to bust," said Bridget G. Brennan, the city's special narcotics prosecutor.
It's a surprisingly difficult operation to sit roughly where you intend, and facing the right direction.
The study found that passing through doorways accounted for the largest number of collisions, and was consistently identified as a very difficult operation to perform.
Trump has also promised to beef up immigration enforcement along the border and inside the United States — notably by tripling the number of U.S. Immigration and Customs Enforcement agents — in an expensive and logistically difficult operation to remove millions of people from the country.
If Donald Trump sticks to the immigration pledges that helped drive his presidential election victory, he will begin a clampdown on illegal immigration that would be unprecedented in American history and would require an exorbitantly expensive — and logistically difficult — operation to remove millions from the country while fortifying the border.
A Highways Agency spokesman said: "An exceptionally delicate and difficult operation to repair cracks in the Boston Manor Viaduct on the M4 has been successful and the motorway has now reopened between junctions 2 and 3 to all cars".
Despite division being the most difficult operation to understand, US textbooks present far fewer problems with fraction division than fraction multiplication; the opposite is true in Chinese and Korean textbooks.
The filling process of liquid suspensions is a difficult operation,mainly due to drug settling.
