Sign me up! I've always been envious of those guys with a naturally deep, resonant voice. When I've got a sore throat, I have a voice like that, but of course it doesn't last, and it's probably not a good idea to over do it when sick.
My understanding is that it takes quite a bit of vocal coaching to develop some of the techniques/tricks learned from opera. I can do throat singing, like Tibetan monks/didgeridoo filter sweeps/whiskeyman blues talk-singing, as well as the high eeeeee that cuts through everything- but in my normal singing voice I struggle, it seems very mysterious to me. I usually feel like my normal singing voice is pretty good when I'm in a situation where I can belt it out like an opera singer in a big room or outdoors- at that point I'm hitting my pitches, have good sustain tone.
To bring more of my "full voice" into my chest voice, for warmups I do a lot of the deep resonance with the throat singing and then try to transition to a chest voice, and then up high to cutting 'eeeeee". Some of what I know as a flute player helps as well: that too is all about sustain to warm up to getting a round, full tone. But voice or flute, I don't have the benefit of opera training. I can see classically trained vocalists doing specific things with their jaw, breathing, posture, but beyond the diaphragm support, I'm not sure what i'm seeing. My buddy who's a great soul singer is always emphasizing good diaphragm support and relaxing into it.
When you open your throat, you jaw should be somewhat like you have an overbite. (your lower jaw actually moves "backward" when you open your mouth. A lot of times people will push their lower jaw out when they hear the term "open throat" regarding singing.) you are taught to sing in what we call "dummy face" (watch some Barbara Streisand videos of her performing, she uses it. she almost looks like a porcelain doll when she sings.) like a ventriloquist's dummy.