Why does Ruskin feel that reading the work of a good author is a painstaking task?

Ruskin feels that reading the work of a good author is a painstaking task as it is not very easy to get into the meaning of the words that the author has written. He says that one has to be prepared to work like an Australian Miner to understand a good book which is born of wisdom. Just as mining is a very painstaking task, so is reading a good book, according to the author. In other words, the essayist means that one has to go through between the lines to understand the pithy words in the good books. Like an Australian miner, one needs patience and hard work to understand the works of the good authors.