There is no requirement to destroy original copies once you have relied on the “administrative purposes” provision.
Indeed, given the limited range of situations in which a library may rely on that provision, and the limited range of people to which administrative copies may be made available (staff and volunteers) it is hard to envisage any situation where, even as a matter of practice, a library would be tempted to destroy an item from which an administrative copy has been made.
While there is no specific requirement to keep hardcopies of material that has been scanned into a database under the “administrative purposes” provision, there are strong incentives to doing so: you are not allowed under the provision to give clients access to such materials in the database, so unless you keep the hardcopies, they will not be able to look at what you have in that database.
In other words, don’t look to the “administrative purposes” provision as a short-cut to building a digital repository. In many cases, if you want to digitise material (particularly material from newspapers and journals) one of the licences offered by CAL may be more suitable to your purposes. http://www.copyright.com.au/Licensing_schemes.aspx
You can only rely on the replacement provision if the item is not commercially available. In our view, the relevant question is whether or not the item by itself is commercially available – that is, for separate purchase.
In this case, as the CD is not available for separate purchase, you would be able to make a replacement copy – for example, from a second copy in your collection or from a copy held by another library.
In our view, the relevant question is whether or not the item that has been lost or damaged is commercially available by itself – that is, for separate purchase.
In this case, as the cassette is not available for separate purchase (either as a cassette or CD), you would be able to make a replacement copy – for example, from a second copy in your collection or from a copy held by another library. If however, you were able to purchase a single CD to replace the lost cassette, you would not be able to rely on the replacement provision in the Act – you should buy the CD.