The Tomb of the Patriarchs

It is a well known fact that our patriarch Abraham lived and died in Hebron. To be more specific, he lived in the cave of Machpelah which he purchased. According to the Old Testament, Abraham would have lived about 3700 years meaning around 1700 BCE. First of all, is there any mention of the year in which Abraham lived and died or is this accepted date simply a rough extraction after analysing the entire text? Has anyone been able to access the cave considering the Herodian structure that covers it? Has there been much archaeological research on the entire structure? Please provide me with any interesting articles you find concerning this topic, thank you.

Edited by Baal Melqart - 17-Sep-2012 at 17:05