The man behind a murder-suicide caravan explosion in Mount Isa stole the explosives from the local mine and intended to also kill his estranged wife, a Queensland coroner has found.

Key points: A Queensland coroner has handed down her report into the deaths of Nyobi Hinder, River Hinder and Charlie Hinder

A Queensland coroner has handed down her report into the deaths of Nyobi Hinder, River Hinder and Charlie Hinder She found Charlie Hinder detonated explosives to kill his children and himself in an act of spousal revenge

She found Charlie Hinder detonated explosives to kill his children and himself in an act of spousal revenge The report highlighted other instances where Hinder had used and stored explosives in the past

Children River Hinder, 4, and Nyobi Hinder, 7, were killed along with their father Charlie Hinder when he blew up the family caravan in the north-west Queensland mining town in July, 2015.

In her report, coroner Nerida Wilson said there was domestic violence in Hinder's relationship with his wife Katherine and he was living in a caravan in the front yard of the family home after the couple separated.

On the morning of the fatal explosion, Ms Hinder arrived home from her nightshift at the local mine and began preparing school lunches for her two children, who she left with their father overnight.

She was on her way to collect them but rather than knocking on the caravan door and disturbing the neighbours, she decided to send a text message instead.

As she found her phone in the kitchen of her home, an explosion occurred that was reported to be felt within a 50-metre radius.

Aerial footage showed the aftermath of the caravan explosion in July, 2015. ( Supplied: Queensland Police Service )

Ms Wilson found Hinder had stolen the four-to-five kilograms of explosives he used while he was employed at the Xstrata Mount Isa Mine (now Glencore) between 2005 and 2008 and on the day of the fatal incident posted a final message on Facebook.

She said he assembled the device and was sitting on a mattress holding the explosive charge "in immediate proximity to the children … perhaps holding or cuddling them" at the time he detonated it.

In her findings, she said Hinder also intended to kill his wife in the explosion, and killed himself and his children as an act of spousal revenge.

All three died instantly.

The explosion was felt up to 50 metres away. ( ABC News )

The coroner agreed with Queensland police and the Department of Natural Resources, Mines and Energy that security systems at the mine between 2005 and 2008 were not sufficient to prevent the opportunistic theft of explosives.

The report also highlighted instances where Hinder used and stored explosives in the past.

On one occasion Hinder dropped Katherine off at the side of the road on a late-night drive, four months after the pair started dating in 2005.

He gave her a camera and told her to film in the direction they had just driven and while Hinder drove further down the road, Katherine heard a loud bang and saw a road sign explode.

The coroner found Charlie Hinder had a history of using explosives. ( ABC News )

He used a 'sausage-style' power-gel explosive to detonate the sign.

After the fatal caravan explosion, Xstrata Mount Isa Mines made a number of significant reforms in regards to handling explosives.

The company updated its explosive storage facilities and implemented an electronic access entry system and video surveillance.