What does Leviticus 5:11-13 actually say in Hebrew, as I had a missionary present to me the following Christian translation of the verse and it appears that the flour offering of atonement was laid on top of the other (animal) sacrificial offerings.
The New Revised Standard Version, Leviticus 5:11-13
But if you cannot afford two turtledoves or two pigeons, you shall bring as your offering for the sin that you have committed one-tenth of an ephah of choice flour for a sin offering; you shall not put oil on it or lay frankincense on it, for it is a sin offering. 12 You shall bring it to the priest, and the priest shall scoop up a handful of it as its memorial portion, and turn this into smoke on the altar, with the offerings by fire to the Lord; it is a sin offering
I've checked a number of Christian translations of the Hebrew scriptures, and they all make a similar error in translating verse 12. The phrase in question is "ee'shay Hashem", which most render as 'the offerings of fire to the L-rd'. This, in fact, is an editorial expansion of the actual phrase. The word "ee'shay" is the construct form of the word "aish" (which means fire), therefore, the correct translation is "fire(s) of Hashem (the L-rd)". The meaning is that the flour is placed on the top of the altar and will be consumed by the fire that is lit on the top of the altar. The phrase does not indicate that the flour is placed on animal sacrifices that were already burning on the altar. First of all, there weren't always animals burning on top of the altar. Even if there were, the altar top was large enough to place the flour elsewhere - not necessarily on top of the animals. Furthermore, most Christian missionaries also make an unwarranted assumption here. Even if they are correct in assuming that the flour is put on top of animals that have already been offered on the altar, there is no reason to assume, as they do, that it is the remnant blood from those sacrifices that gives efficacy to the flour. This is not indicated by the text, which simply says that the flour is the sin offering.