hello wuuscat and welcome to Family Tree Circles,
could you add a little more info, even who he married would be helpful as there were many Joseph O'Brien in New Zealand. Do you have his birth/death dates?

your readers may be interested in the mining disaster you are referring to:

Ralph Mine Disaster HUNTLY, Waikato - Sep 1914
(short bios of each victim at link)
Much has been written about the Ralph Mine Disaster which occurred on 12 September 1914, claiming the lives of 43 men when a miner?s naked light ignited firedamp. It was a Saturday, hence there were only 62 men working instead of the usual 160. Some of them were widowers who left motherless children

* On the 19 April 2009 a memorial board listing all the victims of the Ralph Mine disaster was unveiled at the Huntly Cemetery. The Huntly Lions Club would like to contact with descendants of all the families involved before the centennial in 2014
MINE DISASTER story
Continuing the Rescue Work, 14 September 1814

COMMISSIONERS REPORT, 31 Octobert 1914

c1910 PHOTOS of the
* Ralph Mine at Huntly
* Ralph Mine at Huntly

~~~~~~~~~~~~~~~~~~

DISASTER AT HUNTLY - TERRIBLE MINING EXPLOSION
FIFTY-EIGHT ENTOMBED - EIGHTEEN BODIES RECOVERED
NINETEEN MEN ESCAPE ALIVE - LITTLE HOPE FOR THE OTHERS

Auckland WEEKLY NEWS for Thursday, 17th September 1914
... What will probably prove to be the second greatest mining disaster yet recorded in New Zealand took place on Saturday morning when, as a result of a fearful explosion in Ralph's mine, one of the two Huntly collieries owned by the Taupiri Coal Company Limited, fifty-eight miners were entombed. Of this number nineteen escaped alive, of whom once has since died and at least two others are lying in a serious condition, two at Hamilton Hospital and one in Huntly. The bodies of eighteen of the remaining forty have been recovered, and it is not believed that it is possible to save any of the others alive.
The workings of Ralph's mine extend for miles westward from Huntly, and go under the Waikato River. Experts who had examined it declared it to be one of the safest coal mines in the world, practically free from all forms of dangerous gas. The miners, numbering about 250, habitually worked with naked lights (more at above link)

MINERS WHO LOST THEIR LIVES
Name & Age
ALLEN, William 18
BAKER, Thomas 37
BLENKINSOP, William 37
BERRY, Thomas 29
BOWLER, John 23
BROCKLEBANK, William Snr 52
BURT, Hutchinson 19
BURT, William 28
BURTON, William 27
CASSON, Thomas 22
DARBY, James 57
DIXON, John -
GOWANS, William 43
GREENER, John 48
HINCHCO, William 37
HOLDEN, James 58
HOPPER, Fawcett 31
IZATT, Alexander 17
JACKSON, Henry 24
JACKSON, John 26
JACKSON, Samuel 54
JONES, John 49
KELLY, William 36
LYONS, Daniel 62
MALONEY, Charles 21
MARTIN, John 29
MAYLAND, William Jnr 18
MOLESWORTH, Theophilus 29
MUNSEY, Robert 63
PATERSON, David 36
PATTERSON, William 44
PECKHAM, Henry 45
RANSOME, Hugh 39
ROBINSON, John 28
ROPER, William 36
RUSTON, Arthur 28
SKELLERN, John 36
SLAVIN, William 18
SMITH, William 62
STEELE, John 40
TAYLOR, Fred 29
THOMPSON, Jacob 18
WHORSKEY, John 36

MINERS WHO SURVIVED
BROCKLEBANK, William Jnr
BROWNLIE, Joseph
EARBY, Thomas
FLETCHER, Daniel
HEALEY, Bernard
HUGHES, Thomas
McGILL, Patrick
McINTOSH, Alexander
MITCHELL, William
MOTTRAM, Glen
O'BRIEN, Joseph
PECKHAM, Alfred
RICHARDS, James
RITCHIE, Joseph
STEWART, Albert
TALLON, John
WILKIE, John
YOUNG, James

NOTE
The centennial of the disaster will be held in Huntly this September (2014)

written on 2014-01-25 by wuuscat ... (keeping journals linked)

more info on JOSEPH O'BRIEN Huntly mining disaster