What is the meaning of the phrase: "to lean on the shovel"?

I have recently come accross this phrase in a movie called The Cube. Here is the excerpt:

I leaned on my shovel for months on this one. This was a great job!

I couldn't find any dictionary references that would explain this phrase.

It usually means to do nothing.

It's often used in an expression such as:

"You can't lean on a shovel and pray for a hole."

Meaning that you can't do nothing and expect something to get done.

As for an authoritative source, here's the best I can do. I welcome others to add to this:

The phrase is linked to another phrase, "shovel-ready," used by Franklin Delano Roosevelt to describe the kinds of jobs that the Works Progress Administration would bring to unemployed people as part of the New Deal. He is quoted defending the program, denying that it was created to pay people "to lean on a shovel."

From The Inspiring Story of the True Origin of the Term Shovel-Ready

The phrase refers to scenes that are much less common now than formerly. In developed countries, many construction, labouring or maintenance jobs now done by machines were done up to the middle of the last century largely by hand.

A road gang might dig with picks and shovels to excavate a hole, to refill it, to shovel asphalt into position, to rake material flat, to pass a roller over to smooth the surface. During such work there were periods when those who had been shovelling material would stand aside to allow others to pick, to rake, to roll.

In these circumstances those leaning on their shovels were merely waiting their turn to resume their part in the work. To casual or thoughtless onlookers it appeared as if they were lazy and unproductive.

It is still possible to see such scenes today, where machines are being used and manual labour complements them. Labourers lean on their shovels while a machine plays its part in the process.

The phrase therefore is sometimes used to imply a break in a task and sometimes an unwillingness to work.