The two parts of the Vedas should not be thought of as opposites but rather complementary. One part consists of dharma, the other part with moksha. In his book A Critical Survey of Indian Philosophy, Dr. Prof. Chandradhar Sharma writes (pp 211-12):
The word Mimamsa literally means ‘revered thought’ and was originally applied to the interpretation of the Vedic rituals which commanded highest reverence. The word is now used in the sense of critical investigation. The school of Mimamsa justifies both these meanings by giving us rules according to which the commandments of the Veda are ti be interpreted and by giving a philosophical justification for the Vedic ritualism. Just as Sankhya and Yoga, Vaishesika and Nyaya are regarded as allied systems, similarly Mimamsa and Vedanta are also treated as allied systems of thought. Both are based on and both try to interpret the Veda. The earlier portion of the Veda, i.e., the Mantra and Brahmana portion is called the Karmakanda, while the latter portion, i.e., the Upanishads is called Jnanakanda, because the former deals with action, with the rituals and sacrifice, while the latter deals with the knowledge of reality. Mimamsa deals with the earlier portion of the Veda and is therefore called the Purva-Mimamsa and also Karma-Mimamsa, while the Vedanta delas the latter portion of the Veda and is therefore called Uttara-Mimamsa and also Jnana-Mimamsa. The former deals with Dharma and the latter with Brahma[n] and therefore the former is called the Dharma-Mimamsa, while the latter is also called Brahma-Mimamsa. There has been a long line of pre-Shankarite teachers of Vedanta of whom Mandana Mishra seems to be the last, who have regarded Mimamsa and Vedanta as forming a single system and who advocated the combination of action and knowledge, known as Karma-Jnana-samuchchaya-vada. According to them, the sutras, beginning with the first sutra of Jaimini and ending with the last sutra of Badarayana, form one compact shastra. These teachers held that Karma (action) and Upasana (meditation) were absolutely necessary to hasten the dawn of true knowledge. Even the great Shankaracharya who treated action and knowledge as being absolutely opposed like darkness and light and who relegated Karma to the sphere of Avidya, had to admit that Karma and Upasana do purify the soul, though they are not the direct cause of liberation and that therefore the study of Purva Mimamsa, though not essential for the study of the Vedanta, was a good means for the purification of the soul. In this connection it is also important to remember that it is the great Mimamsaka Kumarila Bhatta himself who may rightly regarded as the link between the Purva and the Uttara Mimamsa. Ramanuja and Bhaskara believe that the Purva and Uttara Mimamsa together form one science and the study of the former is necessary before undertaking the study of the latter. Madhva and Vallabha, though they make devotion to God as a necessary prerequisite for the study of Vedanta, yet believe that Vedanta is a continuation of Mimamasa.
Purva Mimamsa regards the veda as eternal and authorless and of infallible authority. It is essentially a book of ritual dealing with commandments prescribing injunctions or prohibitions. Greatest importance is attached to the Brahmana portion of the Veda to which both the Mantras and Upanishads are subordinated. The aim of the Mimamsa is to supple the principles according to which Vedic texts are to be interpreted and to provide philosophical justification for the views contained therein. The work of finding the principles for the right interpretation of the Vedic texts was undertaken by the Brahmanas themselves and mainly by the Shrauta-sutras. Mimamsa continues this work. But had it done only that, it would have been, at best, only a commentary on Vedic ritual. The main thing which entitles it to the rank of a philosophical system is its keen desire to provide philosophical justification for the Vedic views and to replace the earlier ideal of the attainment of heaven (svarga) by the ideal of obtaining liberation (apavarga). It undertakes a thorough investigation into the nature and validity of knowledge and into the various means which produce valid knowledge and also into other metaphysical problems. Curious though it may seem, the Mimamsa has been influenced by the Nyaya-Vaishesika school, many important doctrines of which it has either borrowed or rejected.
The earliest school of this system is the Mimamsa-sutra of Jaimini which begins with an inquiry into the nature of Dharma. It is the biggest of all philosophical sutras and discusses about one thousand topics. Shabarasvamin has written his great commentary on this work and his commentary on this work and his commentary has been explained by by Prabhakara and Kumarila Bhatta who differ from each other in certain important aspects and form the principle schools of Mimamsa named after them. Prabhakara's commentary Brhati has been commented upon by Shalikanatha who has also written another treatise Prakarana-panchika. Kumarila's huge work is divided into three parts--Shlokavartika, Tantravartika and Tuptika, the first of which has been commented upon by Parthasarathi a pupil of Kumarila who nicknamed him as 'Guru' on account of his great intellectual powers. But some scholars like Dr. Ganganatha Jha believe that the Prabhakara school is older and seems to be nearer the spirit of the original Mimamsa.
So you can see by the above quote Shankara was not entirely opposed to the Mimamsa. For Jaimini's view, it depends upon which school's commentary of Mimamsa you follow. Kumarila is seen now as the bridge from the Mimamsa school to the Uttata school.