Opera mini browser crash issue is a common issue for the mobile phones that are running with java based operating system.
There are two main causes for Opera Mini browser crashing.
1. Browser version not compatible with the phone Operating System.
2. Not sufficient memory available on phone.
Try below options to solve this problem.
1. Make sufficient free space on your phone memory.
2. Upgrade your phone software with latest version and install compatible version of Opera Mini browser.