Go to State Records website.
Click Guides & Finding Aids.
Under Archives in Brief, click on: "For a list of AIB by subject see Archives in Brief 51".
Click on Convicts, court, police and prison.
Click on Inquest Records.
This will give you "Archives In Brief 4 - Inquest and coronial records".
Also, Archives Investigator is helpful to see various record series -
On the home page click on Archives Investigator.
Click on Simple Search.
Type Coroner in keywords search box.
The results will include many Agencies & Record Series to look at. This is where you will find record series for a particular place too. However searching on Coroner Maitland brings up no records unfortunately. I think I may have read somewhere that they no longer exist (please check this yourself).
You've probably checked Trove Newspapers but just in case:
'CRUSHED TO DEATH.
Thomas McNamara, employed on the north-coast railway works at Wallarobba, was crushed by a horse and cart rolling down an embankment where a tunnel is in course of construction. Mr McNamara, sustained such severe internal injuries that be died in the Maitland Hospital.'
The Advertiser Thursday 2 July 1908 pg 8
Also Maitland Family History Circle (Maitland & District Genealogical Society Inc) published a 2 book set you may be able to get a hold of at a library.
Death in the Hunter (2 book set)
Book 1: The Names.
Coroner's Inquests & Magisterial Inquiries Maitland & District 1834-1942
Book 2: The Reports:
Some News Reports of Inquests from the Newspaper
Hope you find what you need.