This is a simple one stage multi.
At the posted coordinates, you will find 6 memorial headstones honouring some of the pioneers of the Sarina area.
By examining these headstones, you will find the numbers to complete the coordinates for the cache location.
The cache is located at S21o 24.ABC E149o 13.XYZ
A Margaret Rae Williams entered into rest in 190A
B James Muggleton died aged 5B years
C Hannah Jane Muggleton died in 190C
X Charlotte Atherton departed this life 190X
Y Edmund Atherton departed this life February Yth
Z Hilma Biltoft died 189Z