I read the bank underground blog post. It is fine and interesting, but it is talking entirely about bank money creation (loans/deposits) and not about base money or capital ratios. That's OK, no reason for an article to talk about everything. But just because one article doesn't talk about capital in the point it is making, doesn't mean that capital is not an important constraint in banking.

https://en.wikipedia.org/wiki/Capital_requirement

There is a reason why bank CEOs have been in recent years judged heavily on their Tier 1 capital ratios, and why they consider it difficult to adjust these ratios. Issuing a new loan makes the bank's capital ratio worse not better.

http://www.forbes.com/sites/greatspeculations/2015/03/06/a-l...