The beginning of the amazing events at Krakatoa in 1883 date to May 20 when there were initial rumblings and venting from the volcano, which had been dormant for about 200 years.
A refinery margin is the revenue associated with refining petroleum, expressed as a value per volume (e.g. $/L), net of the cost of the crude oil input. The simplest refining
can result low competition for market share and higher fuel prices. 2010 to the end of 2014 (Figure 3). for 56% of the variation in the refining margin over this period. The change is the refining margin is calculated using the data shown in Figure 1. The change in the crude oil discount is the spread between the Canadian light oil and the international light oil price (landed in Montreal) shown