The 2009_12_29_Opbmmusic.zip file you have requested: Modifications / Black Mesa / Operation Black Mesa soundtrack - 55.9mb is not available. Perhaps try browsing all files for the game Half-Life 2 and upload any files you want to share or are missing. This is the only information we could locate:
Operation Black Mesa is a total Source conversion of Half Life: Opposing Force. Half-life: Opposing Force is still an amazing game, although its not nearly as amazing as it was when it was released.