The phrase "announcements about which" is correct and usable in written English.
It can be used when referring to specific announcements and indicating that further information or details will follow regarding those announcements.
Example: "The announcements about which we spoke earlier will be made public next week."
Alternatives: "announcements concerning" or "announcements related to".
He was the only person waiting who was alone, apart from herself, and he didn't seem interested in the announcements about which buses were arriving or about to go.
Many manufactuers have information posted on the user forums of their Web sites (Motorola's information is here, for example) and some carriers are starting to make announcements about which phones will be officially upgraded to Ice Cream Sandwich; Verizon Wireless recently posted its list.
And so, unsurprisingly, following the revelations, there was a windfall of announcements about which companies were using it (and were not using it) to collect information; lawsuits over privacy violations and legislation drafted to tighten controls for the future.
In between songs, he made cheesy announcements about which girls should come to the stage and who should go see the cashier.
So far, we only know which cities Dusky will be hitting and when check out for yourself on the flyer below but official announcements about which venues they'll appear at will drop on June 16.
After all, on 30 April, Disney is making an announcement about Infinity which will involve the arrival of Marvel and possibly Star Wars play sets.
They warned that Mr. Trump's Dec. 6 announcement about Jerusalem, which upended decades of American policy, threatened to subvert the effort to solve one of the world's most intractable conflicts.
It's hard to explain the mixture of pride and misgiving that greets each announcement from my mother about which new crisis she will be attending in her work as a nurse for Médecins Sans Frontières (a non-governmental organisation that provides humanitarian aid in crisis zones).
Topbutton.com is pretty current with announcements about warehouse sales which can be the source of some once-in-a-lifetime type bargains.
The announcement comes amid new questions about which officials inside the C.I.A. were involved in the decision to destroy the videotapes, which showed severe interrogation methods used on two Qaeda suspects, Abu Zubaydah and Abd al-Rahim al-Nashiri.
