axm cash: burning or piling up?

Davo, stagman, Bizzo, gself, goygt, tt,

Here's a calculation that may be over-simplistic, so please check and pull apart:
AXM cash at end of Jun Qtr: $10.3M
Costs over Jun Qtr (excluding share issue and including interest): $18.7M.

Let's say geotech problems, etc increase Sep Qtr costs by $1.3M to $20M.

Gold sold in Jul: 10400oz. Let's say gold sold in Aug equals gold produced in Jul: 6400oz, and gold sold in Sep equals estimated Aug production: 7000oz. That's a total for Sep Qtr of 23800oz and at the price forward sold until Dec ($1148/oz), will bring in about $27M.

(At costs of $20M, 23800oz will equate to average cost of $840/oz for Sep Qtr)

So, very roughly, cash at end of Sep will be 10.3-20+27= $17.3M. $7M more than end of June.

If Dec Qtr production is at target 30koz ($34.4M) and costs again $20M, cash at end of Dec will be $31.7M.

Where have I gone wrong and by how much?