The people differed on him, although the majority seem to have considered him Thiqah.
They include Yahya ibn Ma'in, an-Nasa'i, Al-'Ajli etc. Bukhari, Ibn Hibban and Ibn Khuzaimah have narrated from him in their Sahihs (where they only include authentic narrations).
His student Shu'bah has narrated from him, and it is said that he only narrated from those he considered thiqah. However it is also claimed that he stopped narrating from him when he heard the sound of music and singing from his house. But other scholars have noted that this is not a valid objection since it is based on negative speculation, he did not ask him about it so it is possible that there was some explanation or that Minhal was unaware of it happening.
As mentioned above, he is among the narrators relied upon by Bukhari. You can find his mention and details in Fath al-Bari's preface under the section: أسماء من طعن فيه من رجال البخاري, which is a section on criticized narrators.
Among the ahadith that Bukhari narrated from him in his Sahih includes:
حدثنا عثمان بن أبي شيبة، حدثنا جرير، عن منصور، عن المنهال، عن سعيد بن جبير، عن ابن عباس رضي الله عنهما، قال: كان النبي صلى الله عليه وسلم يعوذ الحسن والحسين، ويقول: إن أباكما كان يعوذ بها إسماعيل وإسحاق: أعوذ بكلمات الله التامة، من كل شيطان وهامة، ومن كل عين لامة
... from Minhal from Saeed ibn Jubayr from Ibn Abbas that he said:
The Prophet (ﷺ) used to seek Refuge with Allah for Al-Hasan and Al-Husain and say: "Your forefather (i.e. Abraham) used to seek Refuge with Allah for Ishmael and Isaac by reciting the following: 'O Allah! I seek Refuge with Your Perfect Words from every devil and from poisonous pests and from every evil, harmful, envious eye.'